diff --git a/src/main/java/org/radarbase/appserver/repository/NotificationRepository.java b/src/main/java/org/radarbase/appserver/repository/NotificationRepository.java
index dc423098..c45a890b 100644
--- a/src/main/java/org/radarbase/appserver/repository/NotificationRepository.java
+++ b/src/main/java/org/radarbase/appserver/repository/NotificationRepository.java
@@ -37,8 +37,12 @@ public interface NotificationRepository extends JpaRepository<Notification, Long
 
     List<Notification> findByUserIdAndTaskId(Long userId, Long taskId);
 
+    List<Notification> findByTaskId(Long id);
+
     void deleteByUserId(Long userId);
 
+    void deleteByTaskId(Long taskId);
+
     void deleteByUserIdAndTaskId(Long userId, Long taskId);
 
     boolean existsByUserIdAndSourceIdAndScheduledTimeAndTitleAndBodyAndTypeAndTtlSeconds(
@@ -63,6 +67,8 @@ Optional<Notification> findByUserIdAndSourceIdAndScheduledTimeAndTitleAndBodyAnd
 
     boolean existsById(@NotNull Long id);
 
+    boolean existsByTaskId(Long taskId);
+
     void deleteByFcmMessageId(String fcmMessageId);
 
     void deleteByIdAndUserId(Long id, Long userId);
diff --git a/src/main/java/org/radarbase/appserver/service/FcmNotificationService.java b/src/main/java/org/radarbase/appserver/service/FcmNotificationService.java
index 20d4d20a..6d3ca2f9 100644
--- a/src/main/java/org/radarbase/appserver/service/FcmNotificationService.java
+++ b/src/main/java/org/radarbase/appserver/service/FcmNotificationService.java
@@ -31,6 +31,7 @@
 import org.radarbase.appserver.dto.fcm.FcmNotifications;
 import org.radarbase.appserver.entity.Notification;
 import org.radarbase.appserver.entity.Project;
+import org.radarbase.appserver.entity.Task;
 import org.radarbase.appserver.entity.User;
 import org.radarbase.appserver.event.state.MessageState;
 import org.radarbase.appserver.event.state.dto.NotificationStateEventDto;
@@ -368,6 +369,16 @@ public void removeNotificationsForUserUsingFcmToken(String fcmToken) {
                 });
     }
 
+    @Transactional
+    public void deleteNotificationsByTaskId(Task task) {
+        Long taskId = task.getId();
+        if(notificationRepository.existsByTaskId(taskId)) {
+            List<Notification> notifications = notificationRepository.findByTaskId(taskId);
+            schedulerService.deleteScheduledMultiple(notifications);
+            notificationRepository.deleteByTaskId(taskId);
+        }
+    }
+
     @Transactional
     public FcmNotifications addNotifications(
             FcmNotifications notificationDtos, String subjectId, String projectId, boolean schedule) {
diff --git a/src/main/java/org/radarbase/appserver/service/TaskStateEventService.java b/src/main/java/org/radarbase/appserver/service/TaskStateEventService.java
index d2495006..94f30bf7 100644
--- a/src/main/java/org/radarbase/appserver/service/TaskStateEventService.java
+++ b/src/main/java/org/radarbase/appserver/service/TaskStateEventService.java
@@ -57,6 +57,7 @@ public class TaskStateEventService {
 
     private final transient TaskStateEventRepository taskStateEventRepository;
     private final transient TaskService taskService;
+    private final transient FcmNotificationService notificationService;
 
     private final transient ApplicationEventPublisher taskApplicationEventPublisher;
     private final transient ObjectMapper objectMapper;
@@ -65,10 +66,12 @@ public class TaskStateEventService {
     public TaskStateEventService(
             TaskStateEventRepository taskStateEventRepository,
             TaskService taskService,
+            FcmNotificationService notificationService,
             ApplicationEventPublisher taskApplicationEventPublisher,
             ObjectMapper objectMapper) {
         this.taskStateEventRepository = taskStateEventRepository;
         this.taskService = taskService;
+        this.notificationService = notificationService;
         this.taskApplicationEventPublisher = taskApplicationEventPublisher;
         this.objectMapper = objectMapper;
     }
@@ -77,6 +80,9 @@ public TaskStateEventService(
     public void addTaskStateEvent(TaskStateEvent taskStateEvent) {
         taskStateEventRepository.save(taskStateEvent);
         taskService.updateTaskStatus(taskStateEvent.getTask(), taskStateEvent.getState());
+        if (taskStateEvent.getState().equals(TaskState.COMPLETED)) {
+            notificationService.deleteNotificationsByTaskId(taskStateEvent.getTask());
+        }
     }
 
     @Transactional(readOnly = true)