diff --git a/trello/board.py b/trello/board.py
index 12c02a6f..a702fad0 100644
--- a/trello/board.py
+++ b/trello/board.py
@@ -394,4 +394,5 @@ def get_last_activity(self):
 		"""
 		json_obj = self.client.fetch_json(
                 '/boards/{0}/dateLastActivity'.format(self.id))
-		return dateparser.parse(json_obj['_value'])
+		if json_obj['_value']:
+			return dateparser.parse(json_obj['_value'])