diff --git a/gluon/validators.py b/gluon/validators.py
index 7b4294f1..5622249f 100644
--- a/gluon/validators.py
+++ b/gluon/validators.py
@@ -2341,7 +2341,7 @@ class IS_DATETIME(Validator):
             return (ovalue, translate(self.error_message) % self.extremes)
 
     def formatter(self, value):
-        if value is None:
+        if value is None or value == '':
             return None
         format = self.format
         year = value.year