diff --git a/CHANGES b/CHANGES
index 2db62edb4..b47070834 100644
--- a/CHANGES
+++ b/CHANGES
@@ -1,6 +1,8 @@
 Release 0.6.5 (in development)
 ==============================
 
+* #338: Fix running with ``-C`` under Windows.
+
 * Make the ``start-after`` and ``end-before`` options to the
   ``literalinclude`` directive work correctly if not used together.
 
diff --git a/sphinx/application.py b/sphinx/application.py
index 7d5c54392..3817009f7 100644
--- a/sphinx/application.py
+++ b/sphinx/application.py
@@ -94,6 +94,11 @@ class Sphinx(object):
         self.config = Config(confdir, CONFIG_FILENAME, confoverrides, self.tags)
         self.config.check_unicode(self.warn)
 
+        # set confdir to srcdir if -C given (!= no confdir); a few pieces
+        # of code expect a confdir to be set
+        if self.confdir is None:
+            self.confdir = self.srcdir
+
         # load all extension modules
         for extension in self.config.extensions:
             self.setup_extension(extension)