diff --git a/code/docker-compose.yml b/code/docker-compose.yml
index 261f24f..fa26e95 100644
--- a/code/docker-compose.yml
+++ b/code/docker-compose.yml
@@ -109,6 +109,8 @@ services:
       DB_SERVICE_PORT: ${DB_SERVICE_PORT}
       COMMUNITY_SERVICE_HOST: community-service
       COMMUNITY_SERVICE_PORT: ${COMMUNITY_SERVICE_PORT}
+      COMMENT_SERVICE_HOST: comment-service
+      COMMENT_SERVICE_PORT: ${COMMENT_SERVICE_PORT}
     ports:
       - "${THREAD_SERVICE_PORT}:${THREAD_SERVICE_PORT}"
     networks:
diff --git a/code/kubernetes/services/thread-service/deployment.yaml b/code/kubernetes/services/thread-service/deployment.yaml
index 11b9ee9..d86098a 100644
--- a/code/kubernetes/services/thread-service/deployment.yaml
+++ b/code/kubernetes/services/thread-service/deployment.yaml
@@ -45,6 +45,13 @@ spec:
                 configMapKeyRef:
                   name: threadit-config
                   key: COMMUNITY_SERVICE_PORT
+            - name: COMMENT_SERVICE_HOST
+              value: "comment-service"
+            - name: COMMENT_SERVICE_PORT
+              valueFrom:
+                configMapKeyRef:
+                  name: threadit-config
+                  key: COMMENT_SERVICE_PORT
           readinessProbe:
             tcpSocket:
               port: 50053
diff --git a/code/services/db-service/src/comments.go b/code/services/db-service/src/comments.go
index aa6349e..2976324 100644
--- a/code/services/db-service/src/comments.go
+++ b/code/services/db-service/src/comments.go
@@ -16,7 +16,7 @@ func (s *DBServer) ListComments(ctx context.Context, req *dbpb.ListCommentsReque
 	collection := s.Mongo.Collection("comments")
 	filter := bson.M{}
 	if req.GetThreadId() != "" {
-		filter["thread_id"] = req.GetThreadId()
+		filter["parent_id"] = req.GetThreadId()
 	}
 	cursor, err := collection.Find(ctx, filter, getFindOptions(req.Offset, req.Limit, req.GetSortBy()))
 	if err != nil {
diff --git a/code/services/thread-service/main.go b/code/services/thread-service/main.go
index 3c20468..78087bd 100644
--- a/code/services/thread-service/main.go
+++ b/code/services/thread-service/main.go
@@ -1,8 +1,8 @@
 package main
 
 import (
-	"context"
 	"fmt"
+	commentpb "gen/comment-service/pb"
 	communitypb "gen/community-service/pb"
 	dbpb "gen/db-service/pb"
 	threadpb "gen/thread-service/pb"
@@ -47,10 +47,15 @@ func main() {
 	communityConn := connectGrpcClient("COMMUNITY_SERVICE_HOST", "COMMUNITY_SERVICE_PORT")
 	defer communityConn.Close()
 
+	// connect to comment service
+	commentConn := connectGrpcClient("COMMENT_SERVICE_HOST", "COMMENT_SERVICE_PORT")
+	defer commentConn.Close()
+
 	// create thread service with database service
 	threadService := &server.ThreadServer{
 		DBClient:        dbpb.NewDBServiceClient(dbConn),
 		CommunityClient: communitypb.NewCommunityServiceClient(communityConn),
+		CommentClient:   commentpb.NewCommentServiceClient(commentConn),
 	}
 
 	// get env port
@@ -71,13 +76,6 @@ func main() {
 	)
 	threadpb.RegisterThreadServiceServer(grpcServer, threadService)
 
-	// hardcode a thread creation
-	threadService.CreateThread(context.Background(), &threadpb.CreateThreadRequest{
-		CommunityId: "1",
-		Title:       "Hello World",
-		Content:     "This is a test thread",
-	})
-
 	log.Printf("gRPC server is listening on :%s", port)
 	if err := grpcServer.Serve(lis); err != nil {
 		log.Fatalf("failed to serve: %v", err)
diff --git a/code/services/thread-service/src/server.go b/code/services/thread-service/src/server.go
index 2e334a7..a4e84a0 100644
--- a/code/services/thread-service/src/server.go
+++ b/code/services/thread-service/src/server.go
@@ -2,6 +2,7 @@ package server
 
 import (
 	"context"
+	commentpb "gen/comment-service/pb"
 	communitypb "gen/community-service/pb"
 	dbpb "gen/db-service/pb"
 	models "gen/models/pb"
@@ -17,6 +18,7 @@ type ThreadServer struct {
 	threadpb.UnimplementedThreadServiceServer
 	CommunityClient communitypb.CommunityServiceClient
 	DBClient        dbpb.DBServiceClient
+	CommentClient   commentpb.CommentServiceClient
 }
 
 const (
@@ -171,6 +173,24 @@ func (s *ThreadServer) DeleteThread(ctx context.Context, req *threadpb.DeleteThr
 		return nil, err
 	}
 
+	// find all comments from thread
+	comments, err := s.CommentClient.ListComments(ctx, &commentpb.ListCommentsRequest{
+		ThreadId: &req.Id,
+	})
+	if err != nil {
+		return nil, err
+	}
+
+	// delete comments
+	for _, comment := range comments.Comments {
+		_, err = s.CommentClient.DeleteComment(ctx, &commentpb.DeleteCommentRequest{
+			Id: comment.Id,
+		})
+		if err != nil {
+			return nil, err
+		}
+	}
+
 	// delete thread
 	_, err = s.DBClient.DeleteThread(ctx, &dbpb.DeleteThreadRequest{
 		Id: req.Id,