diff --git a/domain_rules.rules.inc b/domain_rules.rules.inc
index 406a11b..beeac82 100644
--- a/domain_rules.rules.inc
+++ b/domain_rules.rules.inc
@@ -134,7 +134,8 @@ function rules_action_set_node_domain($node, $settings) {
     
     $domain = domain_lookup(NULL, $settings['subdomain'], TRUE);
 
-    if ($domain['domain_id']) {
+    if (isset($domain['domain_id'])) {
+        $domain['domain_id'] = ($domain['domain_id'] == 0) ? -1 : $domain['domain_id'];
         $node->domains[$domain['domain_id']] = $domain['domain_id'];
     }
     else {