diff --git a/Source/NSUserDefaults.m b/Source/NSUserDefaults.m
index 219753201..beb9cf55f 100644
--- a/Source/NSUserDefaults.m
+++ b/Source/NSUserDefaults.m
@@ -1100,7 +1100,7 @@ static BOOL isPlistObject(id o)
   if (isPlistObject(value) == NO)
     {
       [NSException raise: NSInvalidArgumentException
-	format: @"attempt to set non propetrty list object for key (%@)",
+	format: @"attempt to set non property list object for key (%@)",
 	defaultName];
     }