diff --git a/Modules/_tkinter.c b/Modules/_tkinter.c
index 241c1a0a4d8..3f5835363ab 100644
--- a/Modules/_tkinter.c
+++ b/Modules/_tkinter.c
@@ -56,7 +56,7 @@ Copyright (C) 1994 Steen Lumholt.
 #error "Tk older than 8.4 not supported"
 #endif
 
-#if TK_VERSION_HEX >= 0x08050000
+#if TK_VERSION_HEX >= 0x08050002
 #define HAVE_LIBTOMMAMTH
 #include <tclTomMath.h>
 #endif