diff --git a/AsbCloudInfrastructure/Services/AuthService.cs b/AsbCloudInfrastructure/Services/AuthService.cs
index f552d92c..04c0621c 100644
--- a/AsbCloudInfrastructure/Services/AuthService.cs
+++ b/AsbCloudInfrastructure/Services/AuthService.cs
@@ -84,9 +84,14 @@ namespace AsbCloudInfrastructure.Services
             if (userDto.Position?.Length > 255)
                 return -5;
 
+            var user = db.Users.FirstOrDefault(u => u.Login == userDto.Login);
+            
+            if(user is not null)
+                return -6;
+
             var salt = GenerateSalt();
 
-            var user = new User
+            var newUser = new User
             {
                 IdCompany = userDto.IdCompany,
                 IdRole = 2, // simple user
@@ -102,14 +107,14 @@ namespace AsbCloudInfrastructure.Services
                 PasswordHash = salt + ComputeHash(salt, userDto.Password),
             };
 
-            db.Users.Add(user);
+            db.Users.Add(newUser);
             try
             {
                 db.SaveChanges();
             }
             catch //(Exception ex)
             {
-                return -6;
+                return -7;
             }
 
             return 0;
diff --git a/AsbCloudWebApi/Controllers/AuthController.cs b/AsbCloudWebApi/Controllers/AuthController.cs
index 09f34522..08db1c7e 100644
--- a/AsbCloudWebApi/Controllers/AuthController.cs
+++ b/AsbCloudWebApi/Controllers/AuthController.cs
@@ -70,6 +70,7 @@ namespace AsbCloudWebApi.Controllers
                 -3 => BadRequest("Email не должен быть длиннее 255 знаков."),
                 -4 => BadRequest("Телефон не должен быть длиннее 50 знаков."),
                 -5 => BadRequest("Название должности не должно быть длиннее 255 символов."),
+                -6 => BadRequest("Пользователь с таким логином уже зарегистрирован."),
                 _ => BadRequest(),
             };
         }