diff --git a/grade/import/xml/lib.php b/grade/import/xml/lib.php
index 3e059f83c4a..3984cca059f 100644
--- a/grade/import/xml/lib.php
+++ b/grade/import/xml/lib.php
@@ -82,7 +82,7 @@ function import_xml_grades($text, $course, &$error) {
             $newgrade->importer   = $USER->id;
 
             // check grade value exists and is a numeric grade
-            if (isset($result['#']['score'][0]['#'])) {
+            if (isset($result['#']['score'][0]['#']) && $result['#']['score'][0]['#'] !== '-') {
                 if (is_numeric($result['#']['score'][0]['#'])) {
                     $newgrade->finalgrade = $result['#']['score'][0]['#'];
                 } else {