diff --git a/cli/src/main/java/org/onosproject/cli/MastersListCommand.java b/cli/src/main/java/org/onosproject/cli/MastersListCommand.java
index abda027..1357d64 100644
--- a/cli/src/main/java/org/onosproject/cli/MastersListCommand.java
+++ b/cli/src/main/java/org/onosproject/cli/MastersListCommand.java
@@ -24,11 +24,11 @@
 import org.onosproject.cluster.ControllerNode;
 import org.onosproject.mastership.MastershipService;
 import org.onosproject.net.DeviceId;
+import org.onosproject.net.device.DeviceService;
 import org.onosproject.utils.Comparators;
 
 import java.util.Collections;
 import java.util.List;
-
 import static com.google.common.collect.Lists.newArrayList;
 
 /**
@@ -42,6 +42,7 @@
     protected void execute() {
         ClusterService service = get(ClusterService.class);
         MastershipService mastershipService = get(MastershipService.class);
+        DeviceService deviceService = get(DeviceService.class);
         List<ControllerNode> nodes = newArrayList(service.getNodes());
         Collections.sort(nodes, Comparators.NODE_COMPARATOR);
 
@@ -50,6 +51,7 @@
         } else {
             for (ControllerNode node : nodes) {
                 List<DeviceId> ids = Lists.newArrayList(mastershipService.getDevicesOf(node.id()));
+                ids.removeIf(did -> deviceService.getDevice(did) == null);
                 Collections.sort(ids, Comparators.ELEMENT_ID_COMPARATOR);
                 print("%s: %d devices", node.id(), ids.size());
                 for (DeviceId deviceId : ids) {
diff --git a/core/api/src/main/java/org/onosproject/mastership/MastershipService.java b/core/api/src/main/java/org/onosproject/mastership/MastershipService.java
index 1d16a44..ee779ab 100644
--- a/core/api/src/main/java/org/onosproject/mastership/MastershipService.java
+++ b/core/api/src/main/java/org/onosproject/mastership/MastershipService.java
@@ -121,6 +121,8 @@
 
     /**
      * Returns the devices for which a controller is master.
+     * <p>
+     * Returned Set may contain DeviceId which no longer exist in the system.
      *
      * @param nodeId the ID of the controller
      * @return a set of device IDs
diff --git a/core/store/dist/src/main/java/org/onosproject/store/mastership/impl/ConsistentDeviceMastershipStore.java b/core/store/dist/src/main/java/org/onosproject/store/mastership/impl/ConsistentDeviceMastershipStore.java
index 696a0db..2e7c527 100644
--- a/core/store/dist/src/main/java/org/onosproject/store/mastership/impl/ConsistentDeviceMastershipStore.java
+++ b/core/store/dist/src/main/java/org/onosproject/store/mastership/impl/ConsistentDeviceMastershipStore.java
@@ -210,6 +210,10 @@
     public Set<DeviceId> getDevices(NodeId nodeId) {
         checkArgument(nodeId != null, NODE_ID_NULL);
 
+        // FIXME This result contains REMOVED device.
+        // MastershipService cannot listen to DeviceEvent to GC removed topic,
+        // since DeviceManager depend on it.
+        // Reference count, etc. at LeadershipService layer?
         return leadershipService
                 .ownedTopics(nodeId)
                 .stream()