diff --git a/blackjackbot/commands/game/commands.py b/blackjackbot/commands/game/commands.py
index 8f33459..428b16e 100644
--- a/blackjackbot/commands/game/commands.py
+++ b/blackjackbot/commands/game/commands.py
@@ -121,12 +121,12 @@ def join_callback(update, context):
 
         # If players are full, replace join keyboard with start keyboard
         if len(game.players) >= game.MAX_PLAYERS:
-            update.effective_message.edit_reply_markup(reply_markup=get_start_keyboard(lang_id))
+            update.effective_message.edit_reply_markup(reply_markup=get_start_keyboard(game.id, lang_id))
     except errors.GameAlreadyRunningException:
         remove_inline_keyboard(update, context)
         update.callback_query.answer(translator("mp_game_already_begun_callback"))
     except errors.MaxPlayersReachedException:
-        update.effective_message.edit_reply_markup(reply_markup=get_start_keyboard(lang_id))
+        update.effective_message.edit_reply_markup(reply_markup=get_start_keyboard(game.id, lang_id))
         update.callback_query.answer(translator("mp_max_players_callback"))
     except errors.PlayerAlreadyExistingException:
         update.callback_query.answer(translator("mp_already_joined_callback"))
diff --git a/blackjackbot/commands/util/functions.py b/blackjackbot/commands/util/functions.py
index 07ab356..eddbb34 100644
--- a/blackjackbot/commands/util/functions.py
+++ b/blackjackbot/commands/util/functions.py
@@ -144,7 +144,13 @@ def get_join_keyboard(game_id, lang_id):
     return InlineKeyboardMarkup(inline_keyboard=[[join_button, start_button]])
 
 
-def get_start_keyboard(lang_id):
+def get_start_keyboard(game_id, lang_id):
+    """
+    Generates a keyboard with only a start button, translated into the given language
+    :param game_id: A unique identifier for each game
+    :param lang_id: The language identifier for a specific chat
+    :return:
+    """
     translator = Translator(lang_id)
-    start_button = InlineKeyboardButton(text=translator("inline_keyboard_start"), callback_data="start")
+    start_button = InlineKeyboardButton(text=translator("inline_keyboard_start"), callback_data="start_{}".format(game_id))
     return InlineKeyboardMarkup(inline_keyboard=[[start_button]])
diff --git a/blackjackbot/commands/util/tests/__init__.py b/blackjackbot/commands/util/tests/__init__.py
new file mode 100644
index 0000000..40a96af
--- /dev/null
+++ b/blackjackbot/commands/util/tests/__init__.py
@@ -0,0 +1 @@
+# -*- coding: utf-8 -*-
diff --git a/blackjackbot/commands/util/tests/functions_test.py b/blackjackbot/commands/util/tests/functions_test.py
new file mode 100644
index 0000000..d70eb1b
--- /dev/null
+++ b/blackjackbot/commands/util/tests/functions_test.py
@@ -0,0 +1,29 @@
+# -*- coding: utf-8 -*-
+import unittest
+
+from blackjackbot import start_callback_handler
+from blackjackbot.commands.util import get_join_keyboard, get_start_keyboard
+
+
+class CommandsUtilFunctionsTest(unittest.TestCase):
+
+    def test_start_keyboard_matches_start_handler(self):
+        """The start button shown when a lobby is full must be handled by the start callback handler"""
+        game_id = 1234567
+        keyboard = get_start_keyboard(game_id, "en")
+        start_button = keyboard.inline_keyboard[0][0]
+
+        self.assertEqual("start_{}".format(game_id), start_button.callback_data)
+        self.assertTrue(start_callback_handler.pattern.match(start_button.callback_data))
+
+    def test_join_keyboard_start_button_matches_start_handler(self):
+        """The start button of the join keyboard must be handled by the start callback handler"""
+        game_id = 7654321
+        keyboard = get_join_keyboard(game_id, "en")
+        start_button = keyboard.inline_keyboard[0][1]
+
+        self.assertTrue(start_callback_handler.pattern.match(start_button.callback_data))
+
+
+if __name__ == '__main__':
+    unittest.main()