diff --git a/includes/service.inc b/includes/service.inc
index aee00c2..6595be0 100644
--- a/includes/service.inc
+++ b/includes/service.inc
@@ -643,6 +643,7 @@ class SearchApiSolrService extends SearchApiAbstractService {
       $ret = array(
         'search_api_id' => 'item_id',
         'search_api_relevance' => 'score',
+        'search_api_random' => 'random',
       );
 
       // Add the names of any fields configured on the index.
@@ -851,6 +852,16 @@ class SearchApiSolrService extends SearchApiAbstractService {
       if (substr($f, 0, 3) == 'ss_') {
         $f = 'sort_' . substr($f, 3);
       }
+
+      // SOLR provides a "virtual" query-time-only field named "random_SEED" that
+      // can be used to sort randomly the results.
+      if ($field == 'search_api_random') {
+        $params = $query->getOption('search_api_random', array());
+        // Random seed: getting the value from parameters or computing a new ome.
+        $seed = !empty($params['seed']) ? $params['seed'] : rand(1, 200);
+        $f = 'random_' . $seed;
+      }
+
       $order = strtolower($order);
       $sort[$field] = "$f $order";
     }