diff --git a/omniture/account.py b/omniture/account.py
index 243ebb7..026acfa 100644
--- a/omniture/account.py
+++ b/omniture/account.py
@@ -39,7 +39,7 @@ def _serialize_header(self, properties):
     def _build_token(self):
         nonce = str(time.time())
         base64nonce = binascii.b2a_base64(binascii.a2b_qp(nonce))
-        created_date = datetime.today().isoformat() + 'Z'
+        created_date = datetime.utcnow().isoformat() + 'Z'
         sha_object = sha.new(nonce + created_date + self.secret)
         password_64 = binascii.b2a_base64(sha_object.digest())