diff --git a/common/lib/xmodule/xmodule/js/spec/time_spec.js b/common/lib/xmodule/xmodule/js/spec/time_spec.js
index 1941d09959..4790d87d8f 100644
--- a/common/lib/xmodule/xmodule/js/spec/time_spec.js
+++ b/common/lib/xmodule/xmodule/js/spec/time_spec.js
@@ -33,7 +33,7 @@
                     [488,    '00:08:08'], [2452,   '00:40:52'],
                     [3600,   '01:00:00'], [28800,  '08:00:00'],
                     [144532, '40:08:52'], [190360, '52:52:40'],
-                    [294008, '81:40:08']
+                    [294008, '81:40:08'], [-5,     '00:00:00']
                 ];
 
                 $.each(testTimes, function (index, times) {
diff --git a/common/lib/xmodule/xmodule/js/src/time.js b/common/lib/xmodule/xmodule/js/src/time.js
index b4ccb6652c..ab6580e388 100644
--- a/common/lib/xmodule/xmodule/js/src/time.js
+++ b/common/lib/xmodule/xmodule/js/src/time.js
@@ -12,7 +12,7 @@
     function format(time, formatFull) {
         var hours, minutes, seconds;
 
-        if (!_.isFinite(time)) {
+        if (!_.isFinite(time) || time < 0) {
             time = 0;
         }