diff --git a/source/app/controllers/cfdi_xml.py b/source/app/controllers/cfdi_xml.py
index fb61c4b..dee3bfa 100644
--- a/source/app/controllers/cfdi_xml.py
+++ b/source/app/controllers/cfdi_xml.py
@@ -117,7 +117,7 @@ class CFDI(object):
         return
 
     def _relacionados(self, datos):
-        if not datos['tipo'] or not datos['cfdis']:
+        if not datos or not datos['tipo'] or not datos['cfdis']:
             return
 
         node_name = '{}:CfdiRelacionados'.format(self._pre)