diff --git a/acinclude.m4 b/acinclude.m4
index 269b505386c..e347276dddb 100644
--- a/acinclude.m4
+++ b/acinclude.m4
@@ -868,9 +868,9 @@ AC_SUBST(orbit_idl)
 
 AC_DEFUN([MYSQL_CHECK_ISAM], [
   AC_ARG_WITH([isam], [
-  --without-isam          Disable the ISAM table type],
+  --with-isam             Enable the ISAM table type],
     [with_isam="$withval"],
-    [with_isam=yes])
+    [with_isam=no])
 
   isam_libs=
   if test X"$with_isam" = X"yes"