diff --git a/servers/slapd/back-ldap/compare.c b/servers/slapd/back-ldap/compare.c
index 4221d6fbcd..c8033cc164 100644
--- a/servers/slapd/back-ldap/compare.c
+++ b/servers/slapd/back-ldap/compare.c
@@ -74,7 +74,7 @@ ldap_back_compare(
 		return( -1 );
 
 	mapped_at = ldap_back_map(&li->at_map, ava->aa_value->bv_val, 0);
-	if (mapped_oc == NULL)
+	if (mapped_at == NULL)
 		return( -1 );
 
 	ldap_compare_s( lc->ld, mdn, mapped_oc, mapped_at );