diff --git a/lib/dash/mpd_parser.js b/lib/dash/mpd_parser.js
index 0ed867541..e00605078 100644
--- a/lib/dash/mpd_parser.js
+++ b/lib/dash/mpd_parser.js
@@ -975,8 +975,9 @@ shaka.dash.mpd.SegmentTemplate.prototype.parse = function(parent, elem) {
   this.segmentDuration =
       mpd.parseAttr_(elem, 'duration', mpd.parseNonNegativeInt_);
 
+  // The startNumber attribute defaults to 1 but may be set to 0 explicitly.
   this.firstSegmentNumber =
-      mpd.parseAttr_(elem, 'startNumber', mpd.parsePositiveInt_) || 1;
+      mpd.parseAttr_(elem, 'startNumber', mpd.parseNonNegativeInt_) || 1;
 
   this.mediaUrlTemplate = mpd.parseAttr_(elem, 'media', mpd.parseString_);
   this.indexUrlTemplate = mpd.parseAttr_(elem, 'index', mpd.parseString_);