diff --git a/lib/Viewer.js b/lib/Viewer.js
index 71d207d6..7d275bc8 100644
--- a/lib/Viewer.js
+++ b/lib/Viewer.js
@@ -233,7 +233,7 @@ Viewer.prototype.saveSVG = function(options, done) {
       defsNode = domQuery('defs', canvas._svg);
 
   var contents = innerSVG(contentNode),
-      defs = (defsNode && defsNode.outerHTML) || '';
+      defs = defsNode ? '<defs>' + innerSVG(defsNode) + '</defs>' : '';
 
   var bbox = contentNode.getBBox();