diff --git a/src/groups/dao/groups.dao.ts b/src/groups/dao/groups.dao.ts
index 2e053bb8bdf2de3f9d8a9d87e8fef28f8646aac1..e4e557f361aedaaff8dd190cf9ab53781e0f49f7 100644
--- a/src/groups/dao/groups.dao.ts
+++ b/src/groups/dao/groups.dao.ts
@@ -13,8 +13,13 @@ export class GroupsDao {
     private readonly _groupModel: Model<Group>,
   ) {}
 
-  find = (): Observable<Group[]> =>
-    from(this._groupModel.find({})).pipe(map((groups) => [].concat(groups)));
+  find = (): Promise<Group[]> =>
+    new Promise((resolve, reject) => {
+      this._groupModel.find({}, {}, {}, (err, value) => {
+        if (err) reject(err.message);
+        resolve(value);
+      });
+    });
 
   findById = (id: string): Observable<Group | void> =>
     from(this._groupModel.findById(id));
diff --git a/src/groups/groups.controller.ts b/src/groups/groups.controller.ts
index 191fe59226a449282db80421823dd90de5f23100..c9be0429accafe4e9e246edd99edcf516ae4c5ed 100644
--- a/src/groups/groups.controller.ts
+++ b/src/groups/groups.controller.ts
@@ -18,7 +18,7 @@ export class GroupsController {
   constructor(private readonly _groupsService: GroupsService) {}
 
   @Get()
-  findAll(): Observable<GroupEntity[] | void> {
+  findAll(): Promise<GroupEntity[] | void> {
     return this._groupsService.findAll();
   }
 
diff --git a/src/groups/groups.service.ts b/src/groups/groups.service.ts
index 798420c06d7c5a13b5335d4f8b965e2534689157..dc8cf5da08d3ec25c435cdc282ac1210b37ab621 100644
--- a/src/groups/groups.service.ts
+++ b/src/groups/groups.service.ts
@@ -23,12 +23,7 @@ import { GroupEntity } from './entities/group.entity';
 export class GroupsService {
   constructor(private readonly _groupsDao: GroupsDao) {}
 
-  findAll = (): Observable<GroupEntity[] | void> =>
-    this._groupsDao.find().pipe(
-      filter(Boolean),
-      map((groups) => (groups || []).map((group) => new GroupEntity(group))),
-      defaultIfEmpty(undefined),
-    );
+  findAll = (): Promise<GroupEntity[] | void> => this._groupsDao.find();
 
   findOne = (id: string): Observable<GroupEntity> =>
     this._groupsDao.findById(id).pipe(