diff --git a/telethon/_misc/utils.py b/telethon/_misc/utils.py
index 78677142..9121637a 100644
--- a/telethon/_misc/utils.py
+++ b/telethon/_misc/utils.py
@@ -966,7 +966,7 @@ def get_peer_id(peer):
     Extract the integer ID from the given :tl:`Peer`.
     """
     pid = getattr(peer, 'user_id', None) or getattr(peer, 'channel_id', None) or getattr(peer, 'chat_id', None)
-    if not isisintance(pid, int):
+    if not isinstance(pid, int):
         _raise_cast_fail(peer, 'int')
 
     return pid