diff --git a/tests/test_xmljson.py b/tests/test_xmljson.py
index 59bc608..fc1d20a 100644
--- a/tests/test_xmljson.py
+++ b/tests/test_xmljson.py
@@ -362,6 +362,7 @@ def test_etree(self):
             ('x', 'a'),
             ('y', 'b')
         ]), '<x>a</x>', '<y>b</y>')
+        eq({'x': None}, '<x/>')     # None becomes an empty string
         with self.assertRaises(Exception):
             eq({'x': {'@x': 1}}, '<x x="1"/>')
 
diff --git a/xmljson/__init__.py b/xmljson/__init__.py
index 27c6a9a..2fd5e66 100644
--- a/xmljson/__init__.py
+++ b/xmljson/__init__.py
@@ -51,6 +51,8 @@ def _tostring(value):
             value = 'true'
         elif value is False:
             value = 'false'
+        elif value is None:
+            value = ''
         return unicode(value)       # noqa: convert to whatever native unicode repr
 
     @staticmethod