diff --git a/plugins/facetapi/url_processor_standard.inc b/plugins/facetapi/url_processor_standard.inc
index 2019087..7649802 100644
--- a/plugins/facetapi/url_processor_standard.inc
+++ b/plugins/facetapi/url_processor_standard.inc
@@ -46,8 +46,8 @@ class FacetapiUrlProcessorStandard extends FacetapiUrlProcessor {
       }
     }
 
-    // Resets array keys, returns query string.
-    $qstring[$this->filterKey] = array_values($qstring[$this->filterKey]);
+    // Removes duplicates, resets array keys and returns query string.
+    $qstring[$this->filterKey] = array_values(array_unique($qstring[$this->filterKey]));
     return array_filter($qstring);
   }