diff --git a/taxonomy_defaults.module b/taxonomy_defaults.module
index 1788dda..ec84fa2 100644
--- a/taxonomy_defaults.module
+++ b/taxonomy_defaults.module
@@ -82,6 +82,11 @@ function taxonomy_defaults_form_alter(&$form, &$form_state, $form_id) {
       $default_tids = variable_get("taxdef_{$node->type}_{$vid}", array());
       $visible = variable_get("taxdef_{$node->type}_{$vid}_visible", TRUE);
 
+      // Ignore this vocabulary if no default terms are configured.
+      if (count($default_tids) == '0') {
+        continue;
+      }
+
       if ($vocab->tags) {
         // for freetag vocabs, build an array of terms and convert to a string
         $terms = array();