diff --git a/steam/webauth.py b/steam/webauth.py
index 1b2c8fc..1a989a0 100644
--- a/steam/webauth.py
+++ b/steam/webauth.py
@@ -112,7 +112,7 @@ class WebAuth(object):
                                      timeout=15,
                                      data={
                                          'username': username,
-                                         'donotchache': int(time() * 1000),
+                                         'donotcache': int(time() * 1000),
                                          },
                                      ).json()
         except requests.exceptions.RequestException as e: