diff --git a/requests/models.py b/requests/models.py
index da6dccdc..2727bee9 100644
--- a/requests/models.py
+++ b/requests/models.py
@@ -319,7 +319,7 @@ class PreparedRequest(RequestEncodingMixin, RequestHooksMixin):
         """Prepares the given HTTP method."""
         self.method = method
         if self.method is not None:
-            self.method = self.method.upper()
+            self.method = to_native_string(self.method.upper())
 
     def prepare_url(self, url, params):
         """Prepares the given HTTP URL."""
diff --git a/requests/sessions.py b/requests/sessions.py
index 496fdb2e..ad63902a 100644
--- a/requests/sessions.py
+++ b/requests/sessions.py
@@ -438,9 +438,6 @@ class Session(SessionRedirectMixin):
         :param cert: (optional) if String, path to ssl client cert file (.pem).
             If Tuple, ('cert', 'key') pair.
         """
-
-        method = to_native_string(method)
-
         # Create the Request.
         req = Request(
             method = method.upper(),