diff --git a/monasca_common/validation/metrics.py b/monasca_common/validation/metrics.py
index e0ef0199..de69adea 100644
--- a/monasca_common/validation/metrics.py
+++ b/monasca_common/validation/metrics.py
@@ -161,7 +161,7 @@ def validate_value(value):
 
 
 def validate_timestamp(timestamp):
-    if not isinstance(timestamp, (int, float)):
+    if not isinstance(timestamp, (int, long, float)):
         msg = "invalid timestamp type: {0} is not a number type for " \
               "metric".format(timestamp)
         raise InvalidTimeStamp(msg)