diff --git a/lib/carto/tree/layer.js b/lib/carto/tree/layer.js
index c1b3f55..24e61ce 100644
--- a/lib/carto/tree/layer.js
+++ b/lib/carto/tree/layer.js
@@ -22,7 +22,7 @@ tree.LayerXML = function(obj, styles) {
         ' name="' + obj.name + '"\n' +
         prop_string +
         ((typeof obj.status === 'undefined') ? '' : '  status="' + obj.status + '"\n') +
-        '  srs="' + obj.srs + '">\n    ' +
+        ((typeof obj.srs === 'undefined') ? '' : '  srs="' + obj.srs + '"') + '>\n    ' +
         styles.reverse().map(function(s) {
             return '<StyleName>' + s + '</StyleName>';
         }).join('\n    ') +