diff --git a/ago.py b/ago.py
index 694bfaf..1022a36 100644
--- a/ago.py
+++ b/ago.py
@@ -17,7 +17,8 @@ def human(dt, precision=2, past_tense='{} ago', future_tense='in {}', abbreviate
     """Accept a datetime or timedelta, return a human readable delta string"""
     delta = dt
     if type(dt) is not type(timedelta()):
-        delta = datetime.now() - dt
+        dt_no_tz = dt.replace(tzinfo=None)
+        delta = datetime.now() - dt_no_tz
      
     the_tense = past_tense
     if delta < timedelta(0):