diff --git a/rclcpp/include/rclcpp/executors/multi_threaded_executor.hpp b/rclcpp/include/rclcpp/executors/multi_threaded_executor.hpp
index 30ca1b0..9eb78a1 100644
--- a/rclcpp/include/rclcpp/executors/multi_threaded_executor.hpp
+++ b/rclcpp/include/rclcpp/executors/multi_threaded_executor.hpp
@@ -61,7 +61,6 @@ private:
 
   std::mutex wait_mutex_;
   size_t number_of_threads_;
-  std::unordered_map<std::thread::id, size_t> thread_number_by_thread_id_;
 };
 
 }  // namespace multi_threaded_executor
diff --git a/rclcpp/src/rclcpp/executors/multi_threaded_executor.cpp b/rclcpp/src/rclcpp/executors/multi_threaded_executor.cpp
index 0be93f8..1be631a 100644
--- a/rclcpp/src/rclcpp/executors/multi_threaded_executor.cpp
+++ b/rclcpp/src/rclcpp/executors/multi_threaded_executor.cpp
@@ -64,9 +64,8 @@ MultiThreadedExecutor::get_number_of_threads()
 }
 
 void
-MultiThreadedExecutor::run(size_t this_thread_number)
+MultiThreadedExecutor::run(size_t)
 {
-  thread_number_by_thread_id_[std::this_thread::get_id()] = this_thread_number;
   while (rclcpp::utilities::ok() && spinning.load()) {
     executor::AnyExecutable::SharedPtr any_exec;
     {