diff --git a/SessionCompanion/SessionCompanion/Controllers/UserController.cs b/SessionCompanion/SessionCompanion/Controllers/UserController.cs
index 0f8f9d7..7074092 100644
--- a/SessionCompanion/SessionCompanion/Controllers/UserController.cs
+++ b/SessionCompanion/SessionCompanion/Controllers/UserController.cs
@@ -6,13 +6,16 @@ using System.Threading.Tasks;
 namespace SessionCompanion.Controllers
 {
     using System;
+    using System.Collections.Generic;
+    using System.Linq;
     using System.Security.Policy;
 
     using Microsoft.AspNetCore.SignalR;
-
+    using SessionCompanion.Database.Tables;
     using SessionCompanion.Extensions.EitherType;
     using SessionCompanion.Hubs;
     using SessionCompanion.ViewModels.ApiResponses;
+    using SessionCompanion.ViewModels.CharacterViewModels;
     using SessionCompanion.ViewModels.UserViewModels;
 
     [Route("api/user")]
@@ -20,13 +23,15 @@ namespace SessionCompanion.Controllers
     public class UserController : Controller
     {
         private readonly IUserService _service;
+        private readonly ICharacterService _characterService;
 
         private SessionHubData _sessionHubData;
 
-        public UserController(IUserService service)
+        public UserController(IUserService service, ICharacterService characterService)
         {
             this._service = service;
             this._sessionHubData = new SessionHubData();
+            this._characterService = characterService;
         }
 
         /// <summary>
@@ -41,13 +46,31 @@ namespace SessionCompanion.Controllers
             UserViewModel user = await _service.SearchUserByUsername(userName);
 
             if (user != null && user.Password.Equals(password))
-                return user.Id;
+            {
+                List<int> userCharactersIds = _characterService.Get(c => c.UserId.Equals(user.Id)).Result.Select(c => c.Id).ToList();
 
-            return new ErrorResponse()
-                       {
-                           StatusCode = 403,
-                           Message = "User name not found or incorrect password"
-            };
+                foreach(int characterId in userCharactersIds)
+                {
+                    if (SessionHubData.ConnectedCharacters.ContainsKey(characterId))
+                    {
+                        return new ErrorResponse()
+                        {
+                            StatusCode = 403,
+                            Message = "User is already logged in"
+                        };
+                    }
+                }
+
+                return user.Id;
+            }
+            else
+            {
+                return new ErrorResponse()
+                {
+                    StatusCode = 403,
+                    Message = "User name not found or incorrect password"
+                };
+            }
         }