diff --git a/backend/code/src/rooms/dto/change-owner.dto.ts b/backend/code/src/rooms/dto/change-owner.dto.ts
index ea537f9..d95a09d 100644
--- a/backend/code/src/rooms/dto/change-owner.dto.ts
+++ b/backend/code/src/rooms/dto/change-owner.dto.ts
@@ -1,16 +1,13 @@
-// import { ApiProperty } from '@nestjs/swagger';
-import {
-  IsNotEmpty,
-  IsString,
-} from 'class-validator';
+import { ApiProperty } from '@nestjs/swagger';
+import { IsNotEmpty, IsString } from 'class-validator';
 
-export class ChangeOwnerDto{
-    // @ApiProperty()
-    @IsNotEmpty()
-    @IsString()
-    roomId: string;
-    @IsNotEmpty()
-    @IsString()
-    NewOwnerId: string;
-
-}
\ No newline at end of file
+export class ChangeOwnerDto {
+  @ApiProperty()
+  @IsNotEmpty()
+  @IsString()
+  roomId: string;
+  @ApiProperty()
+  @IsNotEmpty()
+  @IsString()
+  NewOwnerId: string;
+}
diff --git a/backend/code/src/rooms/dto/set-admin.dto.ts b/backend/code/src/rooms/dto/set-admin.dto.ts
new file mode 100644
index 0000000..6c9600c
--- /dev/null
+++ b/backend/code/src/rooms/dto/set-admin.dto.ts
@@ -0,0 +1,13 @@
+import { ApiProperty } from '@nestjs/swagger';
+import { IsNotEmpty, IsString } from 'class-validator';
+
+export class SetAdminDto {
+  @ApiProperty()
+  @IsNotEmpty()
+  @IsString()
+  roomId: string;
+  @ApiProperty()
+  @IsNotEmpty()
+  @IsString()
+  newAdmin: string;
+}
diff --git a/backend/code/src/rooms/rooms.controller.ts b/backend/code/src/rooms/rooms.controller.ts
index 76ef3d5..eb02b41 100644
--- a/backend/code/src/rooms/rooms.controller.ts
+++ b/backend/code/src/rooms/rooms.controller.ts
@@ -15,6 +15,7 @@ import { LeaveRoomDto } from './dto/leave-room.dto';
 import { DeleteRoomDto } from './dto/delete-room.dto';
 import { UpdateRoomDto } from './dto/update-room.dto';
 import { ChangeOwnerDto } from './dto/change-owner.dto';
+import { SetAdminDto } from './dto/set-admin.dto';
 import { ApiCookieAuth, ApiTags } from '@nestjs/swagger';
 
 @ApiTags('rooms')
@@ -77,7 +78,16 @@ export class RoomsController {
   async changeOwner(
     @Body() roomdata: ChangeOwnerDto,
     @GetCurrentUser('userId') userId: string,
-    ){
+  ) {
     return await this.roomsService.changeOwner(roomdata, userId);
   }
+  @Post('setAdmin')
+  @HttpCode(HttpStatus.OK)
+  @UseGuards(AtGuard)
+  async setAdmin(
+    @Body() roomdata: SetAdminDto,
+    @GetCurrentUser('userId') userId: string,
+  ) {
+    return await this.roomsService.setAdmin(roomdata, userId);
+  }
 }
diff --git a/backend/code/src/rooms/rooms.service.ts b/backend/code/src/rooms/rooms.service.ts
index 7362fa9..c344dac 100644
--- a/backend/code/src/rooms/rooms.service.ts
+++ b/backend/code/src/rooms/rooms.service.ts
@@ -10,6 +10,7 @@ import { JoinRoomDto } from './dto/join-room.dto';
 import { LeaveRoomDto } from './dto/leave-room.dto';
 import { DeleteRoomDto } from './dto/delete-room.dto';
 import { ChangeOwnerDto } from './dto/change-owner.dto';
+import { SetAdminDto } from './dto/set-admin.dto';
 import * as bcrypt from 'bcrypt';
 import { UpdateRoomDto } from './dto/update-room.dto';
 
@@ -125,17 +126,49 @@ export class RoomsService {
     });
   }
   async changeOwner(roomData: ChangeOwnerDto, userId: string) {
-    const { ownerId } = await this.prisma.room.findUnique({
+    const room = await this.prisma.room.findUnique({
       where: { id: roomData.roomId },
       select: { ownerId: true },
     });
-    if (ownerId !== userId)
+    const member = await this.prisma.roomMember.findUnique({
+      where: { unique_user_room: { userId: userId, roomId: roomData.roomId } },
+      select: { id: true },
+    });
+    if (room.ownerId !== userId)
       throw new UnauthorizedException('You are not the owner of this room');
-    const updateRoomOwner = await this.prisma.room.update({
+    if (!member)
+      throw new UnauthorizedException('new owner is not a member of this room');
+    await this.prisma.room.update({
       where: { id: roomData.roomId },
-      data: { owner: { connect: { userId: roomData.NewOwnerId } } }
+      data: { owner: { connect: { userId: roomData.NewOwnerId } } },
     });
-    return { message: 'change roomOwner successfully' };
-  } 
-
+    return { message: 'roomOwner changed successfully' };
+  }
+  async setAdmin(roomData: SetAdminDto, userId: string) {
+    const room = await this.prisma.room.findUnique({
+      where: { id: roomData.roomId },
+      select: { ownerId: true },
+    });
+    const user = await this.prisma.roomMember.findUnique({
+      where: { unique_user_room: { userId: userId, roomId: roomData.roomId } },
+      select: { is_admin: true },
+    });
+    if (room.ownerId !== userId)
+      throw new UnauthorizedException('You are not the owner of this room');
+    if (!user)
+      throw new UnauthorizedException('new admin is not a member of this room');
+    if (user.is_admin || room.ownerId === roomData.newAdmin)
+      throw new UnauthorizedException(
+        'new admin is already an admin of this room',
+      );
+    return await this.prisma.roomMember.update({
+      where: {
+        unique_user_room: {
+          userId: roomData.newAdmin,
+          roomId: roomData.roomId,
+        },
+      },
+      data: { is_admin: true },
+    });
+  }
 }