diff --git a/src/main/java/com/book/backend/domain/opentalk/controller/OpentalkController.java b/src/main/java/com/book/backend/domain/opentalk/controller/OpentalkController.java
index 20ad0966..f13b5c7f 100644
--- a/src/main/java/com/book/backend/domain/opentalk/controller/OpentalkController.java
+++ b/src/main/java/com/book/backend/domain/opentalk/controller/OpentalkController.java
@@ -52,10 +52,10 @@ public ResponseEntity<?> opentalkMain() throws Exception {
 
 
     // [오픈톡 참여하기]
-    @Operation(summary="오픈톡 참여하기", description="isbn, pageSize를 입력으로 받아, 오픈톡 ID, 채팅 내역 반환",
+    @Operation(summary="오픈톡 참여하기", description="isbn, pageSize를 입력으로 받아 오픈톡 ID, 즐찾여부, 채팅 내역 반환",
             parameters = {@Parameter(name = "isbn", description = "책 ISBN"), @Parameter(name = "pageSize", description = "페이지 당 개수")},
-            responses = {@ApiResponse(responseCode = "200", content = @Content(schema = @Schema(implementation = OpentalkResponseDto.class)),
-                    description = OpentalkResponseDto.description)})
+            responses = {@ApiResponse(responseCode = "200", content = @Content(schema = @Schema(implementation = OpentalkJoinResponseDto.class)),
+                    description = OpentalkJoinResponseDto.description)})
     @PostMapping("/join")
     public ResponseEntity<?> joinOpentalk(@RequestParam String isbn, int pageSize) {
         RequestLogger.param(new String[]{"isbn"}, isbn);
diff --git a/src/main/java/com/book/backend/domain/opentalk/dto/OpentalkDto.java b/src/main/java/com/book/backend/domain/opentalk/dto/OpentalkDto.java
index eb5893ca..b3fbe961 100644
--- a/src/main/java/com/book/backend/domain/opentalk/dto/OpentalkDto.java
+++ b/src/main/java/com/book/backend/domain/opentalk/dto/OpentalkDto.java
@@ -9,6 +9,7 @@
 @Setter
 public class OpentalkDto {
     private Long id;
+    private String isbn13;
     private String bookName;
     private String bookImageURL;
 }
diff --git a/src/main/java/com/book/backend/domain/opentalk/dto/OpentalkJoinResponseDto.java b/src/main/java/com/book/backend/domain/opentalk/dto/OpentalkJoinResponseDto.java
index 6d474e60..2404cf6a 100644
--- a/src/main/java/com/book/backend/domain/opentalk/dto/OpentalkJoinResponseDto.java
+++ b/src/main/java/com/book/backend/domain/opentalk/dto/OpentalkJoinResponseDto.java
@@ -10,5 +10,8 @@
 @Builder
 public class OpentalkJoinResponseDto {
     private final Long opentalkId;
+    private final boolean isFavorite; //즐찾 여부
     private final List<MessageResponseDto> messageResponseDto; //nullable
+
+    public static final String description = "opentalkId : 오픈톡 DB ID | isFavorite : 즐찾여부 | messageResponseDto : 0번째 페이지의 채팅 리스트";
 }
diff --git a/src/main/java/com/book/backend/domain/opentalk/service/OpentalkResponseParser.java b/src/main/java/com/book/backend/domain/opentalk/service/OpentalkResponseParser.java
index be07662f..07477d72 100644
--- a/src/main/java/com/book/backend/domain/opentalk/service/OpentalkResponseParser.java
+++ b/src/main/java/com/book/backend/domain/opentalk/service/OpentalkResponseParser.java
@@ -13,6 +13,7 @@ public class OpentalkResponseParser {
     public void setSimpleBookInfo(OpentalkDto opentalkDto, DetailResponseDto responseDto){
         log.trace("OpentalkResponseParser > setSimpleBookInfo()");
 
+        opentalkDto.setIsbn13(responseDto.getBookInfoDto().getIsbn13());
         opentalkDto.setBookName(responseDto.getBookInfoDto().getBookname());
         opentalkDto.setBookImageURL(responseDto.getBookInfoDto().getBookImageURL());
     }
diff --git a/src/main/java/com/book/backend/domain/opentalk/service/OpentalkService.java b/src/main/java/com/book/backend/domain/opentalk/service/OpentalkService.java
index c288d761..a7f352cc 100644
--- a/src/main/java/com/book/backend/domain/opentalk/service/OpentalkService.java
+++ b/src/main/java/com/book/backend/domain/opentalk/service/OpentalkService.java
@@ -139,12 +139,17 @@ public OpentalkJoinResponseDto joinOpentalk(String isbn, int pageSize){
         Long opentalkId = checkExistOpentalk(isbn);
         if(opentalkId == null){
             opentalkId = createOpentalkIdByIsbn(isbn);
-            return OpentalkJoinResponseDto.builder().opentalkId(opentalkId).messageResponseDto(null).build();
+            return OpentalkJoinResponseDto.builder().opentalkId(opentalkId).messageResponseDto(null).isFavorite(false).build();
         }
         Pageable pageRequest = PageRequest.of(0, pageSize, Sort.by("createdAt").descending());
         Page<Message> messagePage = messageService.getMessage(opentalkId, pageRequest);
         List<MessageResponseDto> response = messageService.pageToDto(messagePage);
-        return OpentalkJoinResponseDto.builder().opentalkId(opentalkId).messageResponseDto(response).build();
+
+        // 즐찾 여부
+        UserOpentalk userOpentalk= userOpentalkRepository.findByUserIdAndOpentalkId(userService.loadLoggedinUser(), opentalkRepository.findById(opentalkId).get());
+        boolean isFavorite = userOpentalk != null;
+
+        return OpentalkJoinResponseDto.builder().opentalkId(opentalkId).messageResponseDto(response).isFavorite(isFavorite).build();
     }
 
     @Transactional