diff --git a/src/CHANGELOG b/src/CHANGELOG
index a690776d8..1ef70ae5f 100644
--- a/src/CHANGELOG
+++ b/src/CHANGELOG
@@ -20,6 +20,8 @@ ECL 0.9f
    reference the variable that it was going to initialize, as in
 	(LAMBDA (&OPTIONAL (FOO (1+ FOO))) ...)
 
+ - ext:c-uint-max and ext:c-ulong-max did not have the right bignum value.
+
 * Visible changes:
 
  - Multithreaded ECL now in Windows, either with Microsoft VC++
diff --git a/src/c/main.d b/src/c/main.d
index ab5a61c7a..17e8a6693 100644
--- a/src/c/main.d
+++ b/src/c/main.d
@@ -290,8 +290,8 @@ cl_boot(int argc, char **argv)
 	ECL_SET(@'si::c-int-min', make_integer(INT_MIN));
 	ECL_SET(@'si::c-long-max', make_integer(LONG_MAX));
 	ECL_SET(@'si::c-long-min', make_integer(LONG_MIN));
-	ECL_SET(@'si::c-uint-max', make_integer(UINT_MAX));
-	ECL_SET(@'si::c-ulong-max', make_integer(ULONG_MAX));
+	ECL_SET(@'si::c-uint-max', make_unsigned_integer(UINT_MAX));
+	ECL_SET(@'si::c-ulong-max', make_unsigned_integer(ULONG_MAX));
 
 	init_number();
 	init_unixtime();