diff --git a/Lib/datetime.py b/Lib/datetime.py
index c5eeca4..59f3c68 100644
--- a/Lib/datetime.py
+++ b/Lib/datetime.py
@@ -1360,7 +1360,7 @@
         converter = _time.localtime if tz is None else _time.gmtime
 
         t, frac = divmod(t, 1.0)
-        us = round(frac * 1e6)
+        us = int(frac * 1e6)
 
         # If timestamp is less than one microsecond smaller than a
         # full second, us can be rounded up to 1000000.  In this case,
@@ -1380,7 +1380,7 @@
     def utcfromtimestamp(cls, t):
         "Construct a UTC datetime from a POSIX timestamp (like time.time())."
         t, frac = divmod(t, 1.0)
-        us = round(frac * 1e6)
+        us = int(frac * 1e6)
 
         # If timestamp is less than one microsecond smaller than a
         # full second, us can be rounded up to 1000000.  In this case,