diff --git a/master/buildbot/data/properties.py b/master/buildbot/data/properties.py
index 89f0bc586d05..be21497d8835 100644
--- a/master/buildbot/data/properties.py
+++ b/master/buildbot/data/properties.py
@@ -38,12 +38,12 @@ class BuildPropertiesEndpoint(base.Endpoint):
         /builds/n:buildid/properties
     """
 
+    @defer.inlineCallbacks
     def get(self, resultSpec, kwargs):
-        buildid = kwargs.get("buildid", None)
-        if buildid is None:
-            # fixme: this cannot work...
-            buildid = kwargs.get("build_number")
-        return self.master.db.builds.getBuildProperties(buildid)
+        retriever = base.NestedBuildDataRetriever(self.master, kwargs)
+        buildid = yield retriever.get_build_id()
+        build_properties = yield self.master.db.builds.getBuildProperties(buildid)
+        return build_properties
 
 
 class PropertiesListEndpoint(base.Endpoint):
diff --git a/master/buildbot/test/unit/data/test_properties.py b/master/buildbot/test/unit/data/test_properties.py
index 5e53e25745f5..23390d22e217 100644
--- a/master/buildbot/test/unit/data/test_properties.py
+++ b/master/buildbot/test/unit/data/test_properties.py
@@ -61,11 +61,12 @@ class BuildPropertiesEndpoint(endpoint.EndpointMixin, unittest.TestCase):
     def setUp(self):
         self.setUpEndpoint()
         self.db.insert_test_data([
+            fakedb.Builder(id=1),
             fakedb.Buildset(id=28),
-            fakedb.BuildRequest(id=5, buildsetid=28),
+            fakedb.BuildRequest(id=5, buildsetid=28, builderid=1),
             fakedb.Master(id=3),
             fakedb.Worker(id=42, name="Friday"),
-            fakedb.Build(id=786, buildrequestid=5, masterid=3, workerid=42),
+            fakedb.Build(id=786, buildrequestid=5, masterid=3, workerid=42, builderid=1, number=5),
             fakedb.BuildProperty(buildid=786, name="year", value=1651, source="Wikipedia"),
             fakedb.BuildProperty(buildid=786, name="island_name", value="despair", source="Book"),
         ])
@@ -81,7 +82,7 @@ def test_get_properties(self):
 
     @defer.inlineCallbacks
     def test_get_properties_from_builder(self):
-        props = yield self.callGet(('builders', 1, 'builds', 786, 'properties'))
+        props = yield self.callGet(('builders', 1, 'builds', 5, 'properties'))
         self.assertEqual(props, {'year': (1651, 'Wikipedia'), 'island_name': ("despair", 'Book')})
 
 
diff --git a/newsfragments/data-BuildPropertiesEndpoint.bugfix b/newsfragments/data-BuildPropertiesEndpoint.bugfix
new file mode 100644
index 000000000000..4075a9096d0a
--- /dev/null
+++ b/newsfragments/data-BuildPropertiesEndpoint.bugfix
@@ -0,0 +1 @@
+``/builders/n:builderid/builds/n:build_number/properties`` endpoint would use ``build_number`` as ``buildid``
\ No newline at end of file