diff --git a/src/command_line.cc b/src/command_line.cc
index 4ce29e20..7b338de7 100644
--- a/src/command_line.cc
+++ b/src/command_line.cc
@@ -728,6 +728,18 @@ struct IndexManager {
   }
 };
 
+// Sends indexing progress to client.
+void EmitProgress(QueueManager* queue) {
+  Out_Progress out;
+  out.params.indexRequestCount = queue->index_request.Size();
+  out.params.doIdMapCount = queue->do_id_map.Size();
+  out.params.loadPreviousIndexCount = queue->load_previous_index.Size();
+  out.params.onIdMappedCount = queue->on_id_mapped.Size();
+  out.params.onIndexedCount = queue->on_indexed.Size();
+
+  IpcManager::instance()->SendOutMessageToClient(IpcId::Cout, out);
+}
+
 }  // namespace
 
 ////////////////////////////////////////////////////////////////////////////////
@@ -1131,6 +1143,8 @@ WorkThread::Result IndexMain(Config* config,
                              WorkingFiles* working_files,
                              MultiQueueWaiter* waiter,
                              QueueManager* queue) {
+  EmitProgress(queue);
+
   // TODO: dispose of index after it is not used for a while.
   clang::Index index(1, 0);
 
@@ -1174,6 +1188,8 @@ bool QueryDb_ImportMain(Config* config,
                         ImportManager* import_manager,
                         QueueManager* queue,
                         WorkingFiles* working_files) {
+  EmitProgress(queue);
+
   bool did_work = false;
 
   while (true) {
diff --git a/src/language_server_api.h b/src/language_server_api.h
index 2b5d6785..1e4d3383 100644
--- a/src/language_server_api.h
+++ b/src/language_server_api.h
@@ -1654,6 +1654,25 @@ void Reflect(TVisitor& visitor, Out_ShowLogMessage& value) {
   REFLECT_MEMBER_END();
 }
 
+struct Out_Progress : public lsOutMessage<Out_Progress> {
+  struct Params {
+    int indexRequestCount = 0;
+    int doIdMapCount = 0;
+    int loadPreviousIndexCount = 0;
+    int onIdMappedCount = 0;
+    int onIndexedCount = 0;
+  };
+  std::string method = "$cquery/progress";
+  Params params;
+};
+MAKE_REFLECT_STRUCT(Out_Progress::Params,
+                    indexRequestCount,
+                    doIdMapCount,
+                    loadPreviousIndexCount,
+                    onIdMappedCount,
+                    onIndexedCount);
+MAKE_REFLECT_STRUCT(Out_Progress, jsonrpc, method, params);
+
 struct Out_CquerySetInactiveRegion
     : public lsOutMessage<Out_CquerySetInactiveRegion> {
   struct Params {
diff --git a/src/threaded_queue.h b/src/threaded_queue.h
index d1465c15..74061c4c 100644
--- a/src/threaded_queue.h
+++ b/src/threaded_queue.h
@@ -3,14 +3,12 @@
 #include <optional.h>
 #include "work_thread.h"
 
-
 #include <algorithm>
 #include <atomic>
 #include <condition_variable>
 #include <mutex>
 #include <queue>
 
-
 using std::experimental::nullopt;
 using std::experimental::optional;
 
@@ -66,6 +64,12 @@ struct ThreadedQueue : public BaseThreadQueue {
 
   explicit ThreadedQueue(MultiQueueWaiter* waiter) : waiter_(waiter) {}
 
+  // Returns the number of elements in the queue. This acquires a lock.
+  size_t Size() const {
+    std::lock_guard<std::mutex> lock(mutex_);
+    return priority_.size() + queue_.size();
+  }
+
   // Add an element to the front of the queue.
   void PriorityEnqueue(T&& t) {
     std::lock_guard<std::mutex> lock(mutex_);