diff --git a/msvc/ecl/config.h.msvc6 b/msvc/ecl/config.h.msvc6
index a84d343a6..e944b8290 100644
--- a/msvc/ecl/config.h.msvc6
+++ b/msvc/ecl/config.h.msvc6
@@ -116,6 +116,8 @@
  * but the required headers are not present in all systems. Hence we
  * use autoconf to guess the following values.
  */
+#define ECL_INT_BITS		32
+#define ECL_LONG_BITS		32
 #define FIXNUM_BITS		32
 #define MOST_POSITIVE_FIXNUM	((cl_fixnum)536870911)
 #define MOST_NEGATIVE_FIXNUM	((cl_fixnum)-536870912)