diff --git a/sprockets/mixins/media_type.py b/sprockets/mixins/media_type.py
index 1305377..6965b17 100644
--- a/sprockets/mixins/media_type.py
+++ b/sprockets/mixins/media_type.py
@@ -6,6 +6,7 @@ sprockets.mixins.media_type
 import logging
 
 from ietfparse import algorithms, errors, headers
+from tornado import web
 
 
 version_info = (0, 0, 0)
@@ -74,6 +75,9 @@ class ContentSettings(object):
         self._available_types.append(headers.parse_content_type(content_type))
         self._handlers[content_type] = handler
 
+    def get(self, content_type, default=None):
+        return self._handlers.get(content_type, default)
+
     @classmethod
     def from_application(cls, application):
         """Retrieve the content settings from an application."""
@@ -186,11 +190,28 @@ class ContentMixin(object):
         return self._best_response_match
 
     def get_request_body(self):
-        """Fetch (and cache) the request body as a dictionary."""
+        """
+        Fetch (and cache) the request body as a dictionary.
+
+        :raise web.HTTPError: if the content type cannot be decoded.
+            The status code is set to 415 Unsupported Media Type
+
+        """
         if self._request_body is None:
             settings = ContentSettings.from_application(self.application)
-            handler = settings[settings.default_content_type]
-            self._request_body = handler.from_bytes(self.request.body)
+            content_type_header = headers.parse_content_type(
+                self.request.headers.get('Content-Type',
+                                         settings.default_content_type))
+            content_type = '/'.join([content_type_header.content_type,
+                                     content_type_header.content_subtype])
+            try:
+                handler = settings[content_type]
+                self._request_body = handler.from_bytes(self.request.body)
+
+            except KeyError:
+                raise web.HTTPError(415, 'cannot decode body of type %s',
+                                    content_type)
+
         return self._request_body
 
     def send_response(self, body, set_content_type=True):
diff --git a/tests.py b/tests.py
index 390fa1b..e815601 100644
--- a/tests.py
+++ b/tests.py
@@ -1,16 +1,18 @@
+import json
+
 from tornado import testing
+import msgpack
 
 import examples
 
 
-class ContentTypeTests(testing.AsyncHTTPTestCase):
+class SendResponseTests(testing.AsyncHTTPTestCase):
 
     def get_app(self):
         return examples.make_application(debug=True)
 
     def test_that_content_type_default_works(self):
-        response = self.fetch('/', method='POST',
-                              body='{"attribute": "value"}',
+        response = self.fetch('/', method='POST', body='{}',
                               headers={'Content-Type': 'application/json'})
         self.assertEqual(response.code, 200)
         self.assertEqual(response.headers['Content-Type'],
@@ -18,14 +20,42 @@ class ContentTypeTests(testing.AsyncHTTPTestCase):
 
     def test_that_missing_content_type_uses_default(self):
         response = self.fetch('/', method='POST', body='{}',
-                              headers={'Accept': 'application/xml'})
+                              headers={'Accept': 'application/xml',
+                                       'Content-Type': 'application/json'})
         self.assertEqual(response.code, 200)
         self.assertEqual(response.headers['Content-Type'],
                          'application/json; charset="utf-8"')
 
     def test_that_accept_header_is_obeyed(self):
         response = self.fetch('/', method='POST', body='{}',
-                              headers={'Accept': 'application/msgpack'})
+                              headers={'Accept': 'application/msgpack',
+                                       'Content-Type': 'application/json'})
         self.assertEqual(response.code, 200)
         self.assertEqual(response.headers['Content-Type'],
                          'application/msgpack')
+
+
+class GetRequestBodyTests(testing.AsyncHTTPTestCase):
+
+    def get_app(self):
+        return examples.make_application(debug=True)
+
+    def test_that_request_with_unhandled_type_results_in_415(self):
+        response = self.fetch(
+            '/', method='POST', headers={'Content-Type': 'application/xml'},
+            body=(u'<request><name>value</name>'
+                  u'<embedded><utf8>\u2731</utf8></embedded>'
+                  u'</request>').encode('utf-8'))
+        self.assertEqual(response.code, 415)
+
+    def test_that_msgpack_request_returns_default_type(self):
+        body = {
+            'name': 'value',
+            'embedded': {
+                'utf8': u'\u2731'
+            }
+        }
+        response = self.fetch('/', method='POST', body=msgpack.packb(body),
+                              headers={'Content-Type': 'application/msgpack'})
+        self.assertEqual(response.code, 200)
+        self.assertEqual(json.loads(response.body.decode('utf-8')), body)