diff --git a/services/friendService.js b/services/friendService.js
index 0111e1fc4681c7b89acf1802ab2a01e7205bbfdc..f0dd45336a6892030759fcd77b2763b5c1a26979 100644
--- a/services/friendService.js
+++ b/services/friendService.js
@@ -3,7 +3,11 @@
 const { Op } = require('sequelize');
 const Friend = require('../models/Friend');
 const User = require('../models/User');
-const sequelize = require('../config/sequelize'); // 트랜잭션을 위해 추가
+const sequelize = require('../config/sequelize');
+
+// DTO 임포트
+const FriendRequestDTO = require('../dtos/FriendRequestDTO');
+const FriendListDTO = require('../dtos/FriendListDTO');
 
 class FriendService {
     /**
@@ -24,7 +28,7 @@ class FriendService {
      * 친구 요청 보내기
      * @param {number} userId - 친구 요청을 보내는 사용자 ID
      * @param {number} friendId - 친구 요청을 받는 사용자 ID
-     * @returns {Promise<Friend>} - 생성된 친구 요청 객체
+     * @returns {Promise<FriendRequestDTO>} - 생성된 친구 요청 DTO
      * @throws {Error} - 유효하지 않은 요청일 경우
      */
     async sendFriendRequest(userId, friendId) {
@@ -35,12 +39,40 @@ class FriendService {
             throw new Error('Cannot send friend request to yourself');
         }
 
+        // 기존 친구 관계 확인 (이미 친구인 경우)
+        const existingFriend = await Friend.findOne({
+            where: {
+                [Op.or]: [
+                    { requester_id: userId, receiver_id: friendId },
+                    { requester_id: friendId, receiver_id: userId },
+                ],
+                status: 'ACCEPTED',
+            },
+        });
+
+        if (existingFriend) {
+            throw new Error('Friend request already exists');
+        }
+
         try {
-            return await Friend.create({
+            const friendRequest = await Friend.create({
                 requester_id: userId,
                 receiver_id: friendId,
                 status: 'PENDING'
             });
+
+            // DTO로 변환하여 반환
+            const friendRequestWithDetails = await Friend.findByPk(friendRequest.id, {
+                include: [
+                    { model: User, as: 'requester', attributes: ['id', 'name', 'email'] },
+                    { model: User, as: 'receiver', attributes: ['id', 'name', 'email'] }
+                ]
+            });
+
+            // 디버깅을 위해 로그 추가
+            //console.log('FriendRequestWithDetails:', friendRequestWithDetails.toJSON());
+
+            return new FriendRequestDTO(friendRequestWithDetails.toJSON());
         } catch (error) {
             if (error.name === 'SequelizeUniqueConstraintError') {
                 throw new Error('Friend request already exists');
@@ -52,46 +84,48 @@ class FriendService {
     /**
      * 받은 친구 요청 목록 조회
      * @param {number} userId - 요청을 받은 사용자 ID
-     * @returns {Promise<Array>} - 받은 친구 요청 목록
+     * @returns {Promise<Array<FriendRequestDTO>>} - 받은 친구 요청 목록 DTO 배열
      */
     async getReceivedRequests(userId) {
-        return Friend.findAll({
+        const receivedRequests = await Friend.findAll({
             where: {
                 receiver_id: userId,
                 status: 'PENDING'
             },
-            include: [{
-                model: User,
-                as: 'requester',
-                attributes: ['id', 'name', 'email']
-            }]
+            include: [
+                { model: User, as: 'requester', attributes: ['id', 'name', 'email'] },
+                { model: User, as: 'receiver', attributes: ['id', 'name', 'email'] } // 추가
+            ]
         });
+
+        return receivedRequests.map(req => new FriendRequestDTO(req));
     }
 
     /**
      * 보낸 친구 요청 목록 조회
      * @param {number} userId - 요청을 보낸 사용자 ID
-     * @returns {Promise<Array>} - 보낸 친구 요청 목록
+     * @returns {Promise<Array<FriendRequestDTO>>} - 보낸 친구 요청 목록 DTO 배열
      */
     async getSentRequests(userId) {
-        return Friend.findAll({
+        const sentRequests = await Friend.findAll({
             where: {
                 requester_id: userId,
                 status: 'PENDING'
             },
-            include: [{
-                model: User,
-                as: 'receiver',
-                attributes: ['id', 'name', 'email']
-            }]
+            include: [
+                { model: User, as: 'receiver', attributes: ['id', 'name', 'email'] },
+                { model: User, as: 'requester', attributes: ['id', 'name', 'email'] } // 추가
+            ]
         });
+
+        return sentRequests.map(req => new FriendRequestDTO(req));
     }
 
     /**
      * 친구 요청 수락
      * @param {number} userId - 요청을 수락하는 사용자 ID
      * @param {number} friendId - 친구 요청을 보낸 사용자 ID
-     * @returns {Promise<Friend>} - 업데이트된 친구 요청 객체
+     * @returns {Promise<FriendRequestDTO>} - 업데이트된 친구 요청 DTO
      * @throws {Error} - 친구 요청이 존재하지 않을 경우
      */
     async acceptFriendRequest(userId, friendId) {
@@ -113,7 +147,16 @@ class FriendService {
             await request.update({ status: 'ACCEPTED' }, { transaction });
 
             await transaction.commit();
-            return request;
+
+            // DTO로 변환하여 반환
+            const updatedRequest = await Friend.findByPk(request.id, {
+                include: [
+                    { model: User, as: 'requester', attributes: ['id', 'name', 'email'] },
+                    { model: User, as: 'receiver', attributes: ['id', 'name', 'email'] }
+                ]
+            });
+
+            return new FriendRequestDTO(updatedRequest);
         } catch (error) {
             await transaction.rollback();
             throw error;
@@ -146,9 +189,11 @@ class FriendService {
     /**
      * 친구 목록 조회
      * @param {number} userId - 친구 목록을 조회할 사용자 ID
-     * @returns {Promise<Array>} - 친구 목록
+     * @param {number} limit - 한 페이지에 표시할 친구 수
+     * @param {number} offset - 페이징 오프셋
+     * @returns {Promise<Array<FriendListDTO>>} - 친구 목록 DTO 배열
      */
-    async getFriendList(userId) {
+    async getFriendList(userId, limit = 20, offset = 0) {
         const friends = await Friend.findAll({
             where: {
                 [Op.or]: [
@@ -168,22 +213,16 @@ class FriendService {
                     as: 'receiver',
                     attributes: ['id', 'name', 'email']
                 }
-            ]
+            ],
+            order: [['id', 'ASC']], // 일관된 정렬 순서 추가
+            limit,
+            offset
         });
 
-        return friends.map(friend => {
-            const isRequester = friend.requester_id === userId;
-            const friendInfo = isRequester ? friend.receiver : friend.requester;
-
-            return {
-                id: friend.id,
-                status: friend.status,
-                createdAt: friend.createdAt,
-                updatedAt: friend.updatedAt,
-                friendInfo: friendInfo,
-                relationshipType: isRequester ? 'sent' : 'received'
-            };
-        });
+        // 디버깅을 위해 로그 추가
+        //console.log(`getFriendList: Retrieved ${friends.length} friends with limit=${limit} and offset=${offset}`);
+
+        return friends.map(friend => new FriendListDTO(friend, userId));
     }
 
     /**
diff --git a/services/friendService.test.js b/services/friendService.test.js
new file mode 100644
index 0000000000000000000000000000000000000000..3bb320b64e6fe8cd8395e16212403c0c47085fb0
--- /dev/null
+++ b/services/friendService.test.js
@@ -0,0 +1,222 @@
+// test/friendService.test.js
+
+const sequelize = require('../config/sequelize'); // Sequelize 인스턴스 임포트
+const User = require('../models/User');
+const Friend = require('../models/Friend');
+const friendService = require('../services/friendService'); // FriendService 임포트
+
+// Sequelize의 Op를 가져오기 위해 추가
+const { Op } = require('sequelize');
+
+beforeAll(async () => {
+    await sequelize.sync({ force: true });
+});
+
+beforeEach(async () => {
+    await sequelize.sync({ force: true });
+
+    // 더미 사용자 생성
+    await User.bulkCreate([
+        { id: 1, name: 'Alice', email: 'alice@example.com' },
+        { id: 2, name: 'Bob', email: 'bob@example.com' },
+        { id: 3, name: 'Charlie', email: 'charlie@example.com' },
+    ]);
+});
+
+afterAll(async () => {
+    // 모든 테스트가 끝난 후 데이터베이스 연결을 종료합니다.
+    await sequelize.close();
+});
+
+describe('Friend Service', () => {
+    describe('validUser', () => {
+        test('should return user when user exists', async () => {
+            const user = await friendService.validUser(1);
+            expect(user).toBeDefined();
+            expect(user.name).toBe('Alice');
+        });
+
+        test('should throw error when user does not exist', async () => {
+            await expect(friendService.validUser(999)).rejects.toThrow('User not found');
+        });
+    });
+
+    describe('sendFriendRequest', () => {
+        test('should send a friend request successfully', async () => {
+            const friendRequestDTO = await friendService.sendFriendRequest(1, 3); // Alice sends request to Charlie
+            console.log('sendFriendRequest DTO:', friendRequestDTO); // 디버깅을 위한 로그 추가
+            expect(friendRequestDTO).toBeDefined();
+            expect(friendRequestDTO.requester.id).toBe(1); 
+            expect(friendRequestDTO.receiver.id).toBe(3); 
+            expect(friendRequestDTO.status).toBe('PENDING');
+        });
+
+        test('should throw error when sending friend request to self', async () => {
+            await expect(friendService.sendFriendRequest(1, 1)).rejects.toThrow('Cannot send friend request to yourself');
+        });
+
+        test('should throw error when sending duplicate friend request', async () => {
+            // Alice sends a friend request to Bob
+            await friendService.sendFriendRequest(1, 2);
+            // Bob accepts Alice's request
+            await friendService.acceptFriendRequest(2, 1);
+
+            // Alice tries to send another friend request to Bob
+            await expect(friendService.sendFriendRequest(1, 2)).rejects.toThrow('Friend request already exists');
+        });
+
+        test('should throw error when user does not exist', async () => {
+            await expect(friendService.sendFriendRequest(1, 999)).rejects.toThrow('User not found');
+            await expect(friendService.sendFriendRequest(999, 1)).rejects.toThrow('User not found');
+        });
+    });
+
+    describe('getReceivedRequests', () => {
+        test('friend requests', async () => {
+            await friendService.sendFriendRequest(3, 1);
+
+            const receivedRequests = await friendService.getReceivedRequests(1);
+            expect(receivedRequests.length).toBe(1);
+            expect(receivedRequests[0].requester.name).toBe('Charlie');
+        });
+
+        test('not send request', async () => {
+            const receivedRequests = await friendService.getReceivedRequests(2); // Bob has no pending requests
+            expect(receivedRequests.length).toBe(0);
+        });
+    });
+
+    describe('getSentRequests', () => {
+        test('should retrieve sent friend requests', async () => {
+            await friendService.sendFriendRequest(1, 3);
+
+            const sentRequests = await friendService.getSentRequests(1);
+            expect(sentRequests.length).toBe(1);
+            expect(sentRequests[0].receiver.name).toBe('Charlie');
+        });
+
+        test('should return empty array when no sent requests', async () => {
+            const sentRequests = await friendService.getSentRequests(3); // Charlie has not sent any PENDING requests
+            expect(sentRequests.length).toBe(0);
+        });
+    });
+
+    describe('acceptFriendRequest', () => {
+        test('should accept a pending friend request successfully', async () => {
+            await friendService.sendFriendRequest(3, 1);
+
+            const updatedRequestDTO = await friendService.acceptFriendRequest(1, 3);
+            expect(updatedRequestDTO).toBeDefined();
+            expect(updatedRequestDTO.status).toBe('ACCEPTED');
+
+            // Db상태 확인
+            const request = await Friend.findOne({
+                where: {
+                    requester_id: 3,
+                    receiver_id: 1,
+                },
+            });
+            expect(request.status).toBe('ACCEPTED');
+        });
+
+        test('should throw error when accepting non-existing friend request', async () => {
+            await expect(friendService.acceptFriendRequest(1, 999)).rejects.toThrow('Friend request not found');
+        });
+    });
+
+    describe('rejectFriendRequest', () => {
+        test('should reject a pending friend request successfully', async () => {
+            await friendService.sendFriendRequest(2, 3);
+
+            const result = await friendService.rejectFriendRequest(3, 2);
+            expect(result).toBe(1);
+
+            const request = await Friend.findOne({
+                where: {
+                    requester_id: 2,
+                    receiver_id: 3,
+                },
+            });
+            expect(request).toBeNull();
+        });
+
+        test('should throw error when rejecting non-existing friend request', async () => {
+            await expect(friendService.rejectFriendRequest(1, 999)).rejects.toThrow('Friend request not found');
+        });
+    });
+
+    describe('getFriendList', () => {
+        test('should retrieve friend list with correct pagination', async () => {
+            await friendService.sendFriendRequest(1, 2);
+            await friendService.acceptFriendRequest(2, 1);
+
+            await friendService.sendFriendRequest(1, 3);
+            await friendService.acceptFriendRequest(3, 1);
+
+            // 추가 더미데이터 생성
+            for (let i = 4; i <= 23; i++) {
+                // Create dummy users
+                await User.create({
+                    id: i,
+                    name: `User${i}`,
+                    email: `user${i}@example.com`,
+                });
+
+                // Alice랑 친구맺기
+                await friendService.sendFriendRequest(1, i);
+                await friendService.acceptFriendRequest(i, 1);
+            }
+
+            // Alice 친구: Bob (2), Charlie (3), User4부터 User23까지 (총 22명)
+            const limit = 5;
+            const offset = 0;
+            const friendsPage1 = await friendService.getFriendList(1, limit, offset);
+            //console.log('getFriendList Page 1:', friendsPage1); // 디버깅을 위한 로그 추가
+            expect(friendsPage1.length).toBe(limit);
+            const expectedNamesPage1 = ['Bob', 'Charlie', 'User4', 'User5', 'User6'];
+            const receivedNamesPage1 = friendsPage1.map(friend => friend.friendInfo.name);
+            expectedNamesPage1.forEach(name => {
+                expect(receivedNamesPage1).toContain(name);
+            });
+
+            const friendsPage2 = await friendService.getFriendList(1, limit, limit);
+            //console.log('getFriendList Page 2:', friendsPage2); // 디버깅을 위한 로그 추가
+            expect(friendsPage2.length).toBe(limit);
+            const expectedNamesPage2 = ['User7', 'User8', 'User9', 'User10', 'User11'];
+            const receivedNamesPage2 = friendsPage2.map(friend => friend.friendInfo.name);
+            expectedNamesPage2.forEach(name => {
+                expect(receivedNamesPage2).toContain(name);
+            });
+        });
+
+        test('should return empty array when user has no friends', async () => {
+            const friends = await friendService.getFriendList(999); // Non-existing user
+            expect(friends.length).toBe(0);
+        });
+    });
+
+    describe('deleteFriend', () => {
+        test('should delete an existing friend relationship successfully', async () => {
+            await friendService.sendFriendRequest(1, 2);
+            await friendService.acceptFriendRequest(2, 1);
+
+            const result = await friendService.deleteFriend(1, 2);
+            expect(result).toBe(1);
+
+            const relationship = await Friend.findOne({
+                where: {
+                    [Op.or]: [
+                        { requester_id: 1, receiver_id: 2 },
+                        { requester_id: 2, receiver_id: 1 },
+                    ],
+                    status: 'ACCEPTED',
+                },
+            });
+            expect(relationship).toBeNull();
+        });
+
+        test('should throw error when deleting a non-existing friend relationship', async () => {
+            await expect(friendService.deleteFriend(1, 999)).rejects.toThrow('Friend relationship not found');
+        });
+    });
+});
diff --git a/services/scheduleService.js b/services/scheduleService.js
index 1cd9d12f49b82e49bb8dd96bad6d11287e3d8831..97e8951a5eadfc65efeb156b457748b893c7ea0b 100644
--- a/services/scheduleService.js
+++ b/services/scheduleService.js
@@ -1,10 +1,14 @@
+// services/scheduleService.js
+
 const { Op } = require('sequelize');
 const Schedule = require('../models/Schedule');
+const ScheduleResponseDTO = require('../dtos/ScheduleResponseDTO');
+const SchedulesResponseDTO = require('../dtos/SchedulesResponseDTO');
 
 class scheduleService {
 
     /**
-     * transactin wrapper 함수
+     * 트랜잭션 래퍼 함수
      */
     async withTransaction(callback) {
         const transaction = await Schedule.sequelize.transaction();
@@ -28,9 +32,7 @@ class scheduleService {
                 { is_fixed: true },
                 {
                     is_fixed: false,
-                    expiry_date: {
-                        [Op.gt]: new Date()
-                    }
+                    expiry_date: { [Op.gt]: new Date() }
                 }
             ]
         };
@@ -58,11 +60,11 @@ class scheduleService {
         const date = new Date(startTime);
         const day = date.getDay();
         const daysUntilNextMonday = (7 - day + 1) % 7;
-        
+
         const nextMonday = new Date(date);
         nextMonday.setDate(date.getDate() + daysUntilNextMonday);
         nextMonday.setHours(0, 0, 0, 0);  // 자정으로 설정
-        
+
         return nextMonday;
     }
 
@@ -70,7 +72,7 @@ class scheduleService {
      * 사용자 스케줄 생성
      */
     async createSchedule({ userId, title, start_time, end_time, is_fixed }) {
-        return this.withTransaction(async (transaction) => {
+        const schedule = await this.withTransaction(async (transaction) => {
             this.validateScheduleTime(start_time, end_time);
 
             const overlap = await this.checkScheduleOverlap(userId, start_time, end_time);
@@ -89,13 +91,15 @@ class scheduleService {
 
             return Schedule.create(scheduleData, { transaction });
         });
+
+        return new ScheduleResponseDTO(schedule);
     }
 
     /**
      * 사용자 스케줄 수정
      */
     async updateSchedule(id, userId, updateData) {
-        return this.withTransaction(async (transaction) => {
+        const updatedSchedule = await this.withTransaction(async (transaction) => {
             const schedule = await Schedule.findOne({
                 where: { id, user_id: userId },
                 transaction
@@ -108,8 +112,8 @@ class scheduleService {
             this.validateScheduleTime(updateData.start_time, updateData.end_time);
 
             const overlap = await this.checkScheduleOverlap(
-                userId, 
-                updateData.start_time, 
+                userId,
+                updateData.start_time,
                 updateData.end_time,
                 id
             );
@@ -118,17 +122,19 @@ class scheduleService {
             }
 
             const is_fixed = schedule.is_fixed;
-            const updatedData = {
+            const updatedDataWithExpiry = {
                 ...updateData,
                 expiry_date: is_fixed ? null : this.getNextMonday(updateData.start_time),
                 updatedAt: new Date()
             };
-            delete updatedData.is_fixed; 
+            delete updatedDataWithExpiry.is_fixed;
 
-            return schedule.update(updatedData, { transaction });
+            return schedule.update(updatedDataWithExpiry, { transaction });
         });
+
+        return new ScheduleResponseDTO(updatedSchedule);
     }
- 
+
     /**
      * 사용자 스케줄 삭제
      */
@@ -143,19 +149,22 @@ class scheduleService {
                 throw new Error('Schedule not found');
             }
 
-            return true;
+            // 삭제 성공 메시지 반환
+            return { message: 'Schedule successfully deleted' };
         });
     }
-    
+
     /**
      * 해당 사용자의 스케줄 정보 조회
      */
     async getAllSchedules(userId) {
         try {
-            return Schedule.findAll({
+            const schedules = await Schedule.findAll({
                 where: this.getScheduleWhereClause(userId),
                 order: [['start_time', 'ASC']]
             });
+
+            return new SchedulesResponseDTO(schedules);
         } catch (error) {
             throw new Error(`Failed to fetch schedules: ${error.message}`);
         }
@@ -169,29 +178,26 @@ class scheduleService {
             const schedule = await Schedule.findOne({
                 where: this.getScheduleWhereClause(userId, id)
             });
-            
+
             if (!schedule) {
                 throw new Error('Schedule not found');
             }
-            
-            return schedule;
+
+            return new ScheduleResponseDTO(schedule);
         } catch (error) {
             throw new Error(`Failed to fetch schedule: ${error.message}`);
         }
     }
-    
-    
+
     /**
-     * 만료된 유동 스케줄 정리 -> utils에 cron job 추가해서 실행하도록 설정
+     * 만료된 유동 스케줄 정리
      */
     async cleanExpiredSchedules() {
         try {
             await Schedule.destroy({
                 where: {
                     is_fixed: false,
-                    expiry_date: {
-                        [Op.lte]: new Date()
-                    }
+                    expiry_date: { [Op.lte]: new Date() }
                 }
             });
         } catch (error) {
@@ -199,9 +205,8 @@ class scheduleService {
         }
     }
 
-
     /**
-     * 스케줄 중복 검사 -> 기존 스케줄 시간대에 추가 못하도록
+     * 스케줄 중복 검사
      */
     async checkScheduleOverlap(userId, start_time, end_time, excludeId = null) {
         try {
@@ -209,14 +214,12 @@ class scheduleService {
                 user_id: userId,
                 [Op.or]: [
                     {
-                        // 새로운 스케줄이 기존 스케줄 내 존재
                         [Op.and]: [
                             { start_time: { [Op.lte]: start_time } },
                             { end_time: { [Op.gte]: start_time } }
                         ]
                     },
                     {
-                        // 새로운 스케줄이 기존 스케줄을 포함
                         [Op.and]: [
                             { start_time: { [Op.gte]: start_time } },
                             { start_time: { [Op.lte]: end_time } }
@@ -224,11 +227,11 @@ class scheduleService {
                     }
                 ]
             };
-    
+
             if (excludeId) {
                 where.id = { [Op.ne]: excludeId };
             }
-    
+
             const overlappingSchedule = await Schedule.findOne({ where });
             return overlappingSchedule;
         } catch (error) {