diff --git a/ceilometer/api/controllers/v2.py b/ceilometer/api/controllers/v2.py
index 084021020..0b8f648ee 100644
--- a/ceilometer/api/controllers/v2.py
+++ b/ceilometer/api/controllers/v2.py
@@ -514,6 +514,11 @@ class MeterController(rest.RestController):
             if self._id != s.counter_name:
                 raise wsme.exc.InvalidInput('counter_name', s.counter_name,
                                             'should be %s' % self._id)
+
+            s.user_id = (s.user_id or
+                         pecan.request.headers.get('X-User-Id'))
+            s.project_id = (s.project_id or
+                            pecan.request.headers.get('X-Project-Id'))
             if auth_project and auth_project != s.project_id:
                 # non admin user trying to cross post to another project_id
                 auth_msg = 'can not post samples to other projects'
diff --git a/tests/api/v2/post_samples.py b/tests/api/v2/post_samples.py
index 03dbfb2d2..3bb40cb0a 100644
--- a/tests/api/v2/post_samples.py
+++ b/tests/api/v2/post_samples.py
@@ -203,3 +203,29 @@ class TestPostSamples(FunctionalTest):
                     self.assertEquals(data.json[x][k],
                                       '%s:%s' % (s1[x]['project_id'],
                                                  'paperstack'))
+
+    def test_missing_project_user_id(self):
+        """Ensure missing project & user IDs are defaulted appropriately.
+        """
+        s1 = [{'counter_name': 'my_counter_name',
+               'counter_type': 'gauge',
+               'counter_unit': 'instance',
+               'counter_volume': 1,
+               'source': 'closedstack',
+               'resource_id': 'bd9431c1-8d69-4ad3-803a-8d4a6b89fd36',
+               'resource_metadata': {'name1': 'value1',
+                                     'name2': 'value2'}}]
+
+        project_id = 'bc23a9d531064583ace8f67dad60f6bb'
+        user_id = 'fd87807-12d2-4b38-9c70-5f5c2ac427ff'
+        data = self.post_json('/meters/my_counter_name/', s1,
+                              expect_errors=True,
+                              headers={
+                                  'X-Roles': 'chief-bottle-washer',
+                                  'X-Project-Id': project_id,
+                                  'X-User-Id': user_id,
+                              })
+
+        self.assertEquals(data.status_int, 200)
+        self.assertEquals(data.json[0]['project_id'], project_id)
+        self.assertEquals(data.json[0]['user_id'], user_id)