diff --git a/deps/rabbit/src/rabbit_quorum_queue.erl b/deps/rabbit/src/rabbit_quorum_queue.erl
index 63ebda9a0fb3..ea4fb5d46647 100644
--- a/deps/rabbit/src/rabbit_quorum_queue.erl
+++ b/deps/rabbit/src/rabbit_quorum_queue.erl
@@ -713,59 +713,56 @@ restart_server({_, _} = Ref) ->
 -spec delete(amqqueue:amqqueue(),
              boolean(), boolean(),
              rabbit_types:username()) ->
-    {ok, QLen :: non_neg_integer()} |
-    {protocol_error, Type :: atom(), Reason :: string(), Args :: term()}.
-delete(Q, true, _IfEmpty, _ActingUser) when ?amqqueue_is_quorum(Q) ->
-    {protocol_error, not_implemented,
-     "cannot delete ~ts. queue.delete operations with if-unused flag set are not supported by quorum queues",
-     [rabbit_misc:rs(amqqueue:get_name(Q))]};
-delete(Q, _IfUnused, true, _ActingUser) when ?amqqueue_is_quorum(Q) ->
-    {protocol_error, not_implemented,
-     "cannot delete ~ts. queue.delete operations with if-empty flag set are not supported by quorum queues",
-     [rabbit_misc:rs(amqqueue:get_name(Q))]};
-delete(Q, _IfUnused, _IfEmpty, ActingUser) when ?amqqueue_is_quorum(Q) ->
+    {ok, QLen :: non_neg_integer()}.
+delete(Q, IfUnused, IfEmpty, ActingUser) when ?amqqueue_is_quorum(Q) ->
     {Name, _} = amqqueue:get_pid(Q),
     QName = amqqueue:get_name(Q),
     QNodes = get_nodes(Q),
-    %% TODO Quorum queue needs to support consumer tracking for IfUnused
-    Timeout = ?DELETE_TIMEOUT,
-    {ok, ReadyMsgs, _} = stat(Q),
-    Servers = [{Name, Node} || Node <- QNodes],
-    case ra:delete_cluster(Servers, Timeout) of
-        {ok, {_, LeaderNode} = Leader} ->
-            MRef = erlang:monitor(process, Leader),
-            receive
-                {'DOWN', MRef, process, _, _} ->
+
+    {ok, ReadyMsgs, Consumers} = stat(Q),
+    IsEmpty = ReadyMsgs == 0,
+    IsUnused = Consumers == 0,
+    if IfEmpty  and not(IsEmpty)  -> {error, not_empty};
+       IfUnused and not(IsUnused) -> {error,    in_use};
+       true                       ->
+            Timeout = ?DELETE_TIMEOUT,
+            Servers = [{Name, Node} || Node <- QNodes],
+            case ra:delete_cluster(Servers, Timeout) of
+                {ok, {_, LeaderNode} = Leader} ->
+                    MRef = erlang:monitor(process, Leader),
+                    receive
+                        {'DOWN', MRef, process, _, _} ->
                     ok
-            after Timeout ->
-                    erlang:demonitor(MRef, [flush]),
-                    ok = force_delete_queue(Servers)
-            end,
-            notify_decorators(QName, shutdown),
-            ok = delete_queue_data(Q, ActingUser),
-            _ = erpc:call(LeaderNode, rabbit_core_metrics, queue_deleted, [QName],
-                          ?RPC_TIMEOUT),
-            {ok, ReadyMsgs};
-        {error, {no_more_servers_to_try, Errs}} ->
-            case lists:all(fun({{error, noproc}, _}) -> true;
-                              (_) -> false
-                           end, Errs) of
-                true ->
-                    %% If all ra nodes were already down, the delete
-                    %% has succeed
-                    delete_queue_data(Q, ActingUser),
+                    after Timeout ->
+                            erlang:demonitor(MRef, [flush]),
+                            ok = force_delete_queue(Servers)
+                    end,
+                    notify_decorators(QName, shutdown),
+                    ok = delete_queue_data(Q, ActingUser),
+                    _ = erpc:call(LeaderNode, rabbit_core_metrics, queue_deleted, [QName],
+                                  ?RPC_TIMEOUT),
                     {ok, ReadyMsgs};
-                false ->
-                    %% attempt forced deletion of all servers
-                    rabbit_log:warning(
-                      "Could not delete quorum '~ts', not enough nodes "
-                       " online to reach a quorum: ~255p."
+                {error, {no_more_servers_to_try, Errs}} ->
+                    case lists:all(fun({{error, noproc}, _}) -> true;
+                                      (_) -> false
+                                   end, Errs) of
+                true ->
+                            %% If all ra nodes were already down, the delete
+                            %% has succeed
+                            delete_queue_data(Q, ActingUser),
+                            {ok, ReadyMsgs};
+                        false ->
+                            %% attempt forced deletion of all servers
+                            rabbit_log:warning(
+                              "Could not delete quorum '~ts', not enough nodes "
+                              " online to reach a quorum: ~255p."
                        " Attempting force delete.",
-                      [rabbit_misc:rs(QName), Errs]),
-                    ok = force_delete_queue(Servers),
-                    notify_decorators(QName, shutdown),
-                    delete_queue_data(Q, ActingUser),
-                    {ok, ReadyMsgs}
+                              [rabbit_misc:rs(QName), Errs]),
+                            ok = force_delete_queue(Servers),
+                            notify_decorators(QName, shutdown),
+                            delete_queue_data(Q, ActingUser),
+                            {ok, ReadyMsgs}
+                    end
             end
     end.