diff --git a/django/utils/_os.py b/django/utils/_os.py
index f7b279d..2c7b88e 100644
--- a/django/utils/_os.py
+++ b/django/utils/_os.py
@@ -30,17 +30,16 @@ def safe_join(base, *paths):
     The final path must be located inside of the base path component (otherwise
     a ValueError is raised).
     """
-    # We need to use normcase to ensure we don't false-negative on case
-    # insensitive operating systems (like Windows).
     base = force_unicode(base)
     paths = [force_unicode(p) for p in paths]
-    final_path = normcase(abspathu(join(base, *paths)))
-    base_path = normcase(abspathu(base))
+    final_path = abspathu(join(base, *paths))
+    base_path = abspathu(base)
     base_path_len = len(base_path)
-    # Ensure final_path starts with base_path and that the next character after
-    # the final path is os.sep (or nothing, in which case final_path must be
-    # equal to base_path).
-    if not final_path.startswith(base_path) \
+    # Ensure final_path starts with base_path (using normcase to ensure we
+    # don't false-negative on case insensitive operating systems like Windows)
+    # and that the next character after the final path is os.sep (or nothing,
+    # in which case final_path must be equal to base_path).
+    if not normcase(final_path).startswith(normcase(base_path)) \
        or final_path[base_path_len:base_path_len+1] not in ('', sep):
         raise ValueError('The joined path (%s) is located outside of the base '
                          'path component (%s)' % (final_path, base_path))
diff --git a/tests/regressiontests/file_storage/tests.py b/tests/regressiontests/file_storage/tests.py
index e9e9d31..cdec187 100644
--- a/tests/regressiontests/file_storage/tests.py
+++ b/tests/regressiontests/file_storage/tests.py
@@ -90,13 +90,16 @@ class FileStorageTests(unittest.TestCase):
     storage_class = FileSystemStorage
 
     def setUp(self):
-        self.temp_dir = tempfile.mktemp()
-        os.makedirs(self.temp_dir)
+        self.temp_dir = tempfile.mkdtemp()
         self.storage = self.storage_class(location=self.temp_dir,
             base_url='/test_media_url/')
+        # Set up a second temporary directory which is ensured to have a mixed
+        # case name.
+        self.temp_dir2 = tempfile.mkdtemp(suffix='aBc')
 
     def tearDown(self):
         shutil.rmtree(self.temp_dir)
+        shutil.rmtree(self.temp_dir2)
 
     def test_file_access_options(self):
         """
@@ -265,6 +268,20 @@ class FileStorageTests(unittest.TestCase):
         self.assertRaises(SuspiciousOperation, self.storage.exists, '..')
         self.assertRaises(SuspiciousOperation, self.storage.exists, '/etc/passwd')
 
+    def test_file_storage_preserves_filename_case(self):
+        """The storage backend should preserve case of filenames."""
+        # Create a storage backend associated with the mixed case name
+        # directory.
+        temp_storage = self.storage_class(location=self.temp_dir2)
+        # Ask that storage backend to store a file with a mixed case filename.
+        mixed_case = 'CaSe_SeNsItIvE'
+        file = temp_storage.open(mixed_case, 'w')
+        file.write('storage contents')
+        file.close()
+        self.assertEqual(os.path.join(self.temp_dir2, mixed_case),
+                         temp_storage.path(mixed_case))
+        temp_storage.delete(mixed_case)
+
 class CustomStorage(FileSystemStorage):
     def get_available_name(self, name):
         """
diff --git a/tests/regressiontests/file_uploads/tests.py b/tests/regressiontests/file_uploads/tests.py
index 3c126b7..d42e027 100644
--- a/tests/regressiontests/file_uploads/tests.py
+++ b/tests/regressiontests/file_uploads/tests.py
@@ -278,6 +278,37 @@ class FileUploadTests(TestCase):
             # CustomUploadError is the error that should have been raised
             self.assertEqual(err.__class__, uploadhandler.CustomUploadError)
 
+    def test_filename_case_preservation(self):
+        """
+        The storage backend shouldn't mess with the case of the filenames
+        uploaded.
+        """
+        # Synthesize the contents of a file upload with a mixed case filename
+        # so we don't have to carry such a file in the Django tests source code
+        # tree.
+        vars = {'boundary': 'oUrBoUnDaRyStRiNg'}
+        post_data = [
+            '--%(boundary)s',
+            'Content-Disposition: form-data; name="file_field"; '
+                'filename="MiXeD_cAsE.txt"',
+            'Content-Type: application/octet-stream',
+            '',
+            'file contents\n'
+            '',
+            '--%(boundary)s--\r\n',
+        ]
+        response = self.client.post(
+            '/file_uploads/filename_case/',
+            '\r\n'.join(post_data) % vars,
+            'multipart/form-data; boundary=%(boundary)s' % vars
+        )
+        self.assertEqual(response.status_code, 200)
+        id = int(response.content)
+        obj = FileModel.objects.get(pk=id)
+        # The name of the file uploaded and the file stored in the server-side
+        # shouldn't differ.
+        self.assertEqual(os.path.basename(obj.testfile.path), 'MiXeD_cAsE.txt')
+
 class DirectoryCreationTests(unittest.TestCase):
     """
     Tests for error handling during directory creation
diff --git a/tests/regressiontests/file_uploads/urls.py b/tests/regressiontests/file_uploads/urls.py
index 9f814c4..a5c2702 100644
--- a/tests/regressiontests/file_uploads/urls.py
+++ b/tests/regressiontests/file_uploads/urls.py
@@ -11,4 +11,5 @@ urlpatterns = patterns('',
     (r'^quota/broken/$',    views.file_upload_quota_broken),
     (r'^getlist_count/$',   views.file_upload_getlist_count),
     (r'^upload_errors/$',   views.file_upload_errors),
+    (r'^filename_case/$',   views.file_upload_filename_case_view),
 )
diff --git a/tests/regressiontests/file_uploads/views.py b/tests/regressiontests/file_uploads/views.py
index dba7522..c88c775 100644
--- a/tests/regressiontests/file_uploads/views.py
+++ b/tests/regressiontests/file_uploads/views.py
@@ -120,3 +120,12 @@ def file_upload_getlist_count(request):
 def file_upload_errors(request):
     request.upload_handlers.insert(0, ErroringUploadHandler())
     return file_upload_echo(request)
+
+def file_upload_filename_case_view(request):
+    """
+    Check adding the file to the database will preserve the filename case.
+    """
+    file = request.FILES['file_field']
+    obj = FileModel()
+    obj.testfile.save(file.name, file)
+    return HttpResponse('%d' % obj.pk)
diff --git a/tests/regressiontests/templates/tests.py b/tests/regressiontests/templates/tests.py
index abfdb8d..5237bb6 100644
--- a/tests/regressiontests/templates/tests.py
+++ b/tests/regressiontests/templates/tests.py
@@ -161,8 +161,8 @@ class Templates(unittest.TestCase):
         fs_loader = filesystem.Loader()
         def test_template_sources(path, template_dirs, expected_sources):
             if isinstance(expected_sources, list):
-                # Fix expected sources so they are normcased and abspathed
-                expected_sources = [os.path.normcase(os.path.abspath(s)) for s in expected_sources]
+                # Fix expected sources so they are abspathed
+                expected_sources = [os.path.abspath(s) for s in expected_sources]
             # Test the two loaders (app_directores and filesystem).
             func1 = lambda p, t: list(ad_loader.get_template_sources(p, t))
             func2 = lambda p, t: list(fs_loader.get_template_sources(p, t))
@@ -205,9 +205,9 @@ class Templates(unittest.TestCase):
         if os.path.normcase('/TEST') == os.path.normpath('/test'):
             template_dirs = ['/dir1', '/DIR2']
             test_template_sources('index.html', template_dirs,
-                                  ['/dir1/index.html', '/dir2/index.html'])
+                                  ['/dir1/index.html', '/DIR2/index.html'])
             test_template_sources('/DIR1/index.HTML', template_dirs,
-                                  ['/dir1/index.html'])
+                                  ['/DIR1/index.HTML'])
 
     def test_loader_debug_origin(self):
         # Turn TEMPLATE_DEBUG on, so that the origin file name will be kept with
