diff --git a/pandas/core/arrays/datetimes.py b/pandas/core/arrays/datetimes.py
index 0f07a9cf3c0e0..92d397e9ababc 100644
--- a/pandas/core/arrays/datetimes.py
+++ b/pandas/core/arrays/datetimes.py
@@ -239,7 +239,7 @@ def _generate_range(cls, start, end, periods, freq, tz=None,
         if end is not None:
             end = Timestamp(end)
 
-        if start is None and end is None:
+        if start is None or end is None:
             if closed is not None:
                 raise ValueError("Closed has to be None if not both of start"
                                  "and end are defined")