diff --git a/ceilometer/agent/discovery/tenant.py b/ceilometer/agent/discovery/tenant.py
index 6754b85726..c7615f64d5 100644
--- a/ceilometer/agent/discovery/tenant.py
+++ b/ceilometer/agent/discovery/tenant.py
@@ -12,8 +12,12 @@
 # License for the specific language governing permissions and limitations
 # under the License.
 
+from oslo_log import log
+
 from ceilometer.agent import plugin_base as plugin
 
+LOG = log.getLogger(__name__)
+
 
 class TenantDiscovery(plugin.DiscoveryBase):
     """Discovery that supplies keystone tenants.
@@ -24,5 +28,17 @@ class TenantDiscovery(plugin.DiscoveryBase):
     """
 
     def discover(self, manager, param=None):
-        tenants = manager.keystone.projects.list()
+        domains = manager.keystone.domains.list()
+        LOG.debug('Found %s keystone domains', len(domains))
+        if domains:
+            tenants = []
+            for domain in domains:
+                domain_tenants = manager.keystone.projects.list(domain)
+                LOG.debug("Found %s tenants in domain %s", len(domain_tenants),
+                          domain.name)
+                tenants = tenants + domain_tenants
+        else:
+            tenants = manager.keystone.projects.list()
+            LOG.debug("No domains - found %s tenants in default domain",
+                      len(tenants))
         return tenants or []
diff --git a/releasenotes/notes/scan-domains-for-tenants-8f8c9edcb74cc173.yaml b/releasenotes/notes/scan-domains-for-tenants-8f8c9edcb74cc173.yaml
new file mode 100644
index 0000000000..8da87a3a52
--- /dev/null
+++ b/releasenotes/notes/scan-domains-for-tenants-8f8c9edcb74cc173.yaml
@@ -0,0 +1,4 @@
+---
+features:
+  - The tenant (project) discovery code in the polling agent now scans for
+    tenants in all available domains.