diff --git a/requests_mock/adapter.py b/requests_mock/adapter.py
index f2f0f9e..62ad997 100644
--- a/requests_mock/adapter.py
+++ b/requests_mock/adapter.py
@@ -10,6 +10,8 @@
 # License for the specific language governing permissions and limitations
 # under the License.
 
+import json
+
 import requests
 from requests.adapters import BaseAdapter
 import six
@@ -70,6 +72,18 @@ class _RequestObjectProxy(object):
     def _create(cls, *args, **kwargs):
         return cls(requests.Request(*args, **kwargs).prepare())
 
+    @property
+    def text(self):
+        body = self.body
+
+        if isinstance(body, six.binary_type):
+            body = body.decode('utf-8')
+
+        return body
+
+    def json(self, **kwargs):
+        return json.loads(self.text, **kwargs)
+
 
 class _RequestHistoryTracker(object):
 
diff --git a/requests_mock/tests/test_adapter.py b/requests_mock/tests/test_adapter.py
index 600e0bd..b3e96f3 100644
--- a/requests_mock/tests/test_adapter.py
+++ b/requests_mock/tests/test_adapter.py
@@ -10,6 +10,7 @@
 # License for the specific language governing permissions and limitations
 # under the License.
 
+import json
 import re
 
 import requests
@@ -394,3 +395,44 @@ class SessionAdapterTests(base.TestCase):
 
         resp2 = resp1.connection.send(req)
         self.assertEqual(text2, resp2.text)
+
+    def test_request_json_with_str_data(self):
+        dict_req = {'hello': 'world'}
+        dict_resp = {'goodbye': 'world'}
+
+        m = self.adapter.register_uri('POST', self.url, json=dict_resp)
+
+        data = json.dumps(dict_req)
+        resp = self.session.post(self.url, data=data)
+
+        self.assertIs(data, m.last_request.body)
+        self.assertEqual(dict_resp, resp.json())
+        self.assertEqual(dict_req, m.last_request.json())
+
+    def test_request_json_with_bytes_data(self):
+        dict_req = {'hello': 'world'}
+        dict_resp = {'goodbye': 'world'}
+
+        m = self.adapter.register_uri('POST', self.url, json=dict_resp)
+
+        data = json.dumps(dict_req).encode('utf-8')
+        resp = self.session.post(self.url, data=data)
+
+        self.assertIs(data, m.last_request.body)
+        self.assertEqual(dict_resp, resp.json())
+        self.assertEqual(dict_req, m.last_request.json())
+
+    def test_request_json_with_cb(self):
+        dict_req = {'hello': 'world'}
+        dict_resp = {'goodbye': 'world'}
+        data = json.dumps(dict_req)
+
+        def _cb(req, context):
+            self.assertEqual(dict_req, req.json())
+            return dict_resp
+
+        m = self.adapter.register_uri('POST', self.url, json=_cb)
+        resp = self.session.post(self.url, data=data)
+
+        self.assertEqual(1, m.call_count)
+        self.assertEqual(dict_resp, resp.json())