diff --git a/lib/delphi/src/Thrift.Stream.pas b/lib/delphi/src/Thrift.Stream.pas
index d1f6384..74c1782 100644
--- a/lib/delphi/src/Thrift.Stream.pas
+++ b/lib/delphi/src/Thrift.Stream.pas
@@ -140,7 +140,7 @@
 var
   statstg: TStatStg;
   len : Integer;
-  NewPos : Int64;
+  NewPos : {$IF CompilerVersion >= 30.0} UInt64 {$ELSE} Int64  {$IFEND};
   cbRead : Integer;
 begin
   FillChar( statstg, SizeOf( statstg), 0);