diff --git a/setup.py b/setup.py
index 0da7593..9d35734 100644
--- a/setup.py
+++ b/setup.py
@@ -8,7 +8,11 @@ except:
 
 def get_bzr_version():
     import os
-    rev = int(os.popen('bzr revno').read())
+    info = os.path.join(os.path.dirname(__file__), '.bzr/branch/last-revision')
+    if os.path.exists(info):
+        f = open(info)
+        rev = int(f.read().split()[0])
+        f.close()
     if rev:
         return u'%s' % rev
     return u'unknown'