diff --git a/garminexport/garminclient.py b/garminexport/garminclient.py
index 268046b..ee74349 100755
--- a/garminexport/garminclient.py
+++ b/garminexport/garminclient.py
@@ -8,13 +8,14 @@ import logging
 import os
 import re
 import requests
-from StringIO import StringIO
+from io import BytesIO
 import sys
 import zipfile
 import dateutil
 import dateutil.parser
 import os.path
 from functools import wraps
+from builtins import range
 
 #
 # Note: For more detailed information about the API services
@@ -163,7 +164,7 @@ class GarminClient(object):
         batch_size = 100
         # fetch in batches since the API doesn't allow more than a certain
         # number of activities to be retrieved on every invocation
-        for start_index in xrange(0, sys.maxint, batch_size):
+        for start_index in range(0, sys.maxsize, batch_size):
             next_batch = self._fetch_activity_ids_and_ts(start_index, batch_size)
             if not next_batch:
                 break
@@ -332,7 +333,7 @@ class GarminClient(object):
 
         # return the first entry from the zip archive where the filename is
         # activity_id (should be the only entry!)
-        zip = zipfile.ZipFile(StringIO(response.content), mode="r")
+        zip = zipfile.ZipFile(BytesIO(response.content), mode="r")
         for path in zip.namelist():
             fn, ext = os.path.splitext(path)
             if fn==str(activity_id):
diff --git a/requirements.txt b/requirements.txt
index 2a57eaf..b550dab 100644
--- a/requirements.txt
+++ b/requirements.txt
@@ -1,5 +1,6 @@
 requests==2.9.1
 python-dateutil==2.4.1
+future==0.16.0
 
 nose==1.3.7
 coverage==4.2
diff --git a/tests/test_retryer.py b/tests/test_retryer.py
index b3720fd..e2a6d74 100644
--- a/tests/test_retryer.py
+++ b/tests/test_retryer.py
@@ -74,7 +74,7 @@ class TestRetryer(unittest.TestCase):
         func = lambda : int(time.time())
         
         returnval = retryer.call(func)
-        print returnval
+        print(returnval)
         
 
 class TestFixedDelayStrategy(unittest.TestCase):