diff --git a/requirements.txt b/requirements.txt
index ad869cb..89d8d02 100644
--- a/requirements.txt
+++ b/requirements.txt
@@ -1,3 +1,3 @@
 requests>=1.1.0
-winkerberos >= 0.4.0; sys.platform == 'win32'
+winkerberos >= 0.5.0; sys.platform == 'win32'
 pykerberos >= 1.1.8, < 2.0.0; sys.platform != 'win32'
diff --git a/setup.py b/setup.py
index 57d7621..0790a68 100755
--- a/setup.py
+++ b/setup.py
@@ -51,7 +51,7 @@ setup(
         'requests>=1.1.0',
     ],
     extras_require={
-        ':sys_platform=="win32"': ['winkerberos>=0.4.0'],
+        ':sys_platform=="win32"': ['winkerberos>=0.5.0'],
         ':sys_platform!="win32"': ['pykerberos>=1.1.8,<2.0.0'],
     },
     test_suite='test_requests_kerberos',