diff --git a/unique_field.module b/unique_field.module
index 1c72828..356b5fc 100644
--- a/unique_field.module
+++ b/unique_field.module
@@ -10,7 +10,6 @@
  *
  * By Joe Turgeon [http://arithmetric.com]
  */
-
 // query scope definitions
 define('UNIQUE_FIELD_SCOPE_NODE', 'node');
 define('UNIQUE_FIELD_SCOPE_TYPE', 'type');
@@ -268,6 +267,7 @@ function unique_field_match_value($field, $values, $scope, $ntype = NULL, $nlang
   }
   else {
     // Query condition for other fields
+    $field_values = array();
     $field_info = field_info_field($field);
     // Check all items/values
     foreach ($values as $value) {
@@ -281,10 +281,25 @@ function unique_field_match_value($field, $values, $scope, $ntype = NULL, $nlang
         if (!strlen($val) || !is_scalar($val)) {
           continue;
         }
-        $efq->fieldCondition($field, $key, $val);
+        $field_values[] = array('key' => $key, 'val' => $val);
       }
     }
   }
+  if ($field_info->cardinality) {
+    $field_values = reset($field_values);
+    $val = $field_values['val'];
+    $key = $field_values['key'];
+    $efq->fieldCondition($field, $key, $val);
+  }
+  else {
+    $val = array();
+    $key = '';
+    foreach ($field_values as $k => $v) {
+      $val[] = $v['val'];
+      $key = $v['key'];
+    }
+    $efq->fieldCondition($field, $key, $val, 'IN');
+  }
 
   // Add query conditions for the scope setting
   if ($scope === UNIQUE_FIELD_SCOPE_TYPE && !empty($ntype)) {