diff --git a/gunicorn/instrument/statsd.py b/gunicorn/instrument/statsd.py
index e712c47f..5dfe14fa 100644
--- a/gunicorn/instrument/statsd.py
+++ b/gunicorn/instrument/statsd.py
@@ -81,8 +81,8 @@ class Statsd(Logger):
         request_time is a datetime.timedelta
         """
         Logger.access(self, resp, req, environ, request_time)
-        duration_in_s = request_time.seconds + float(request_time.microseconds)/10**6
-        self.histogram("gunicorn.request.duration", duration_in_s)
+        duration_in_ms = request_time.seconds * 1000 + float(request_time.microseconds)/10**3
+        self.histogram("gunicorn.request.duration", duration_in_ms)
         self.increment("gunicorn.requests", 1)
         self.increment("gunicorn.request.status.%d" % int(resp.status.split()[0]), 1)