diff --git a/lib/delphi/src/Thrift.WinHTTP.pas b/lib/delphi/src/Thrift.WinHTTP.pas
index 8d677dd..854d7c0 100644
--- a/lib/delphi/src/Thrift.WinHTTP.pas
+++ b/lib/delphi/src/Thrift.WinHTTP.pas
@@ -739,7 +739,7 @@
                              nil);
     SetString( result, pBuffer, nChars);
   finally
-    LocalFree( Cardinal( pBuffer));
+    LocalFree( NativeUInt( pBuffer));
   end;
 end;