diff --git a/preproc.c b/preproc.c
index 45c02647..b5c95af4 100644
--- a/preproc.c
+++ b/preproc.c
@@ -2150,7 +2150,7 @@ static int do_directive(Token * tline)
             /* All subsequent ARG directives are for a 64-bit stack */
             StackSize = 8;
             StackPointer = "rbp";
-            ArgOffset = 8;
+            ArgOffset = 16;
             LocalOffset = 0;
         } else if (nasm_stricmp(tline->text, "large") == 0) {
             /* All subsequent ARG directives are for a 16-bit stack,