diff --git a/Modules/_tkinter.c b/Modules/_tkinter.c
index bef5c0b..4d9cc0d 100644
--- a/Modules/_tkinter.c
+++ b/Modules/_tkinter.c
@@ -96,7 +96,7 @@
 #error "unsupported Tcl configuration"
 #endif
 
-#if TK_VERSION_HEX >= 0x08050000
+#if TK_VERSION_HEX >= 0x08050002
 #define HAVE_LIBTOMMAMTH
 #include <tclTomMath.h>
 #endif