diff --git a/src/main/java/com/kusitms/jipbap/chat/domain/dto/MessageDto.java b/src/main/java/com/kusitms/jipbap/chat/domain/dto/MessageDto.java
index 1965576..443b5bf 100644
--- a/src/main/java/com/kusitms/jipbap/chat/domain/dto/MessageDto.java
+++ b/src/main/java/com/kusitms/jipbap/chat/domain/dto/MessageDto.java
@@ -15,7 +15,6 @@ public class MessageDto {
     private String senderName;
     private String roomId;
     private String message;
-    private String sentTime;
 
     // 대화 조회
     public MessageDto(Message message) {
diff --git a/src/main/java/com/kusitms/jipbap/chat/domain/dto/MessageResponseDto.java b/src/main/java/com/kusitms/jipbap/chat/domain/dto/MessageResponseDto.java
index 903da35..1aad6d5 100644
--- a/src/main/java/com/kusitms/jipbap/chat/domain/dto/MessageResponseDto.java
+++ b/src/main/java/com/kusitms/jipbap/chat/domain/dto/MessageResponseDto.java
@@ -17,7 +17,7 @@ public class MessageResponseDto {
     private String roomId;
     private String receiver;
     private String message;
-    private String createdAt;
+    private String lastMessageSentTime; // (채팅방 조회시) 메세지 마지막 전송 시각
 
     // 채팅방 생성
     public MessageResponseDto(Room room) {
@@ -46,6 +46,6 @@ public void setLatestMessageContent(String message) {
     }
 
     public void setLatestMessageCreatedAt(String createdAt) {
-        this.createdAt = createdAt;
+        this.lastMessageSentTime = createdAt;
     }
 }
\ No newline at end of file
diff --git a/src/main/java/com/kusitms/jipbap/chat/domain/entity/Message.java b/src/main/java/com/kusitms/jipbap/chat/domain/entity/Message.java
index 36ded5e..e46e770 100644
--- a/src/main/java/com/kusitms/jipbap/chat/domain/entity/Message.java
+++ b/src/main/java/com/kusitms/jipbap/chat/domain/entity/Message.java
@@ -34,4 +34,8 @@ public Message(String senderName, Room room, String message) {
         this.room = room;
         this.message = message;
     }
+
+    public void updateSentTime(String sentTime) {
+        this.sentTime = sentTime;
+    }
 }
\ No newline at end of file
diff --git a/src/main/java/com/kusitms/jipbap/chat/repository/MessageRepository.java b/src/main/java/com/kusitms/jipbap/chat/repository/MessageRepository.java
index 52251d4..3132073 100644
--- a/src/main/java/com/kusitms/jipbap/chat/repository/MessageRepository.java
+++ b/src/main/java/com/kusitms/jipbap/chat/repository/MessageRepository.java
@@ -11,4 +11,5 @@ public interface MessageRepository extends JpaRepository<Message, Long> {
     List<Message> findTop100ByRoomOrderById(Room room);
 
     Message findTopByRoomOrderById(Room room);
+    Message findTopByRoomOrderBySentTimeDesc(Room room);
 }
\ No newline at end of file
diff --git a/src/main/java/com/kusitms/jipbap/chat/service/MessageService.java b/src/main/java/com/kusitms/jipbap/chat/service/MessageService.java
index 84721b2..0e14f05 100644
--- a/src/main/java/com/kusitms/jipbap/chat/service/MessageService.java
+++ b/src/main/java/com/kusitms/jipbap/chat/service/MessageService.java
@@ -14,7 +14,9 @@
 import org.springframework.data.redis.serializer.GenericJackson2JsonRedisSerializer;
 import org.springframework.data.redis.serializer.Jackson2JsonRedisSerializer;
 import org.springframework.stereotype.Service;
+import org.springframework.transaction.annotation.Transactional;
 
+import java.time.LocalDateTime;
 import java.util.ArrayList;
 import java.util.List;
 import java.util.concurrent.TimeUnit;
@@ -29,14 +31,15 @@ public class MessageService {
     private final ObjectMapper objectMapper;
 
     // 메세지 저장
+    @Transactional
     public void saveMessage(MessageDto messageDto) {
         Room room = roomRepository.findByRoomId(messageDto.getRoomId()).orElseThrow(
                 ()->new RoomNotExistsException("채팅방이 더 이상 존재하지 않습니다.")
         );
 
         // DB 저장
-        Message message = new Message(messageDto.getSenderName(), room, messageDto.getMessage());
-        messageRepository.save(message);
+        Message message = messageRepository.save(new Message(messageDto.getSenderName(), room, messageDto.getMessage()));
+        message.updateSentTime(message.getCreatedAt().toString());
 
         // 1. 직렬화
         redisTemplateMessage.setValueSerializer(new GenericJackson2JsonRedisSerializer(objectMapper));
@@ -49,6 +52,7 @@ public void saveMessage(MessageDto messageDto) {
     }
 
     // 6. 대화 조회 - Redis & DB (TLB 캐시전략 유사)
+    @Transactional
     public List<MessageDto> loadMessage(String roomId) {
         List<MessageDto> messageList = new ArrayList<>();
 
diff --git a/src/main/java/com/kusitms/jipbap/chat/service/RoomService.java b/src/main/java/com/kusitms/jipbap/chat/service/RoomService.java
index 0f1039c..99366e9 100644
--- a/src/main/java/com/kusitms/jipbap/chat/service/RoomService.java
+++ b/src/main/java/com/kusitms/jipbap/chat/service/RoomService.java
@@ -22,6 +22,7 @@
 import org.springframework.data.redis.listener.ChannelTopic;
 import org.springframework.data.redis.listener.RedisMessageListenerContainer;
 import org.springframework.stereotype.Service;
+import org.springframework.transaction.annotation.Transactional;
 
 import java.util.ArrayList;
 import java.util.HashMap;
@@ -60,6 +61,7 @@ private void init() {
     }
 
     // 채팅방 생성
+    @Transactional
     public MessageResponseDto createRoom(MessageRequestDto dto, String email) {
         User sender = userRepository.findByEmail(email).orElseThrow(()->new InvalidEmailException("회원정보가 존재하지 않습니다."));
 //        User receiver = userRepository.findById(dto.getReceiverId()).orElseThrow(()->new InvalidEmailException("수신 회원정보가 존재하지 않습니다."));
@@ -82,6 +84,7 @@ public MessageResponseDto createRoom(MessageRequestDto dto, String email) {
     }
 
     // 7. 사용자 관련 채팅방 전체 조회 (생성, 수신)
+    @Transactional
     public List<MessageResponseDto> findAllRoomByUser(String email) {
         User user = userRepository.findByEmail(email).orElseThrow(()->new InvalidEmailException("회원정보가 존재하지 않습니다."));
         List<Room> messageRooms = roomRepository.findByUserOrReceiverName(user, user.getUsername());      // sender & receiver 모두 해당 채팅방 조회 가능 (1:1 대화)
@@ -99,7 +102,7 @@ public List<MessageResponseDto> findAllRoomByUser(String email) {
                         messageRoom.getReceiverName());
 
                 // 8. 가장 최신 메시지 & 생성 시간 조회
-                Message latestMessage = messageRepository.findTopByRoomOrderById(messageRoom);
+                Message latestMessage = messageRepository.findTopByRoomOrderBySentTimeDesc(messageRoom);
                 if (latestMessage != null) {
                     messageRoomDto.setLatestMessageCreatedAt(latestMessage.getSentTime());
                     messageRoomDto.setLatestMessageContent(latestMessage.getMessage());
@@ -116,7 +119,7 @@ public List<MessageResponseDto> findAllRoomByUser(String email) {
                         messageRoom.getReceiverName());
 
                 // 가장 최신 메시지 & 생성 시간 조회
-                Message latestMessage = messageRepository.findTopByRoomOrderById(messageRoom);
+                Message latestMessage = messageRepository.findTopByRoomOrderBySentTimeDesc(messageRoom);
                 if (latestMessage != null) {
                     messageRoomDto.setLatestMessageCreatedAt(latestMessage.getSentTime());
                     messageRoomDto.setLatestMessageContent(latestMessage.getMessage());
@@ -130,6 +133,7 @@ public List<MessageResponseDto> findAllRoomByUser(String email) {
     }
 
     // 사용자 관련 채팅방 선택 조회
+    @Transactional
     public RoomDto findRoom(String roomId, String email) {
         Room room = roomRepository.findByRoomId(roomId).orElseThrow(
                 ()->new RoomNotExistsException("채팅방 정보를 찾을 수 없습니다.")
@@ -163,6 +167,7 @@ public RoomDto findRoom(String roomId, String email) {
     }
 
     // 10. 채팅방 삭제
+    @Transactional
     public void deleteRoom(Long id, String email) {
         User user = userRepository.findByEmail(email).orElseThrow(()->new InvalidEmailException("회원정보가 존재하지 않습니다."));