diff --git a/rmw_zenoh_cpp/src/detail/rmw_client_data.cpp b/rmw_zenoh_cpp/src/detail/rmw_client_data.cpp
index 84ae0328..195f9ff6 100644
--- a/rmw_zenoh_cpp/src/detail/rmw_client_data.cpp
+++ b/rmw_zenoh_cpp/src/detail/rmw_client_data.cpp
@@ -43,10 +43,6 @@
 namespace
 {
 
-std::mutex client_data_ptr_to_shared_ptr_map_mutex;
-std::unordered_map<const rmw_zenoh_cpp::ClientData *,
-  std::shared_ptr<rmw_zenoh_cpp::ClientData>> client_data_ptr_to_shared_ptr_map;
-
 ///=============================================================================
 void client_data_handler(z_owned_reply_t * reply, void * data)
 {
@@ -59,16 +55,7 @@ void client_data_handler(z_owned_reply_t * reply, void * data)
     return;
   }
 
-  std::shared_ptr<rmw_zenoh_cpp::ClientData> client_data_shared_ptr{nullptr};
-  {
-    std::lock_guard<std::mutex> lk(client_data_ptr_to_shared_ptr_map_mutex);
-    if (client_data_ptr_to_shared_ptr_map.count(client_data) == 0) {
-      return;
-    }
-    client_data_shared_ptr = client_data_ptr_to_shared_ptr_map[client_data];
-  }
-
-  if (client_data_shared_ptr->is_shutdown()) {
+  if (client_data->is_shutdown()) {
     return;
   }
 
@@ -94,13 +81,28 @@ void client_data_handler(z_owned_reply_t * reply, void * data)
   std::chrono::nanoseconds::rep received_timestamp =
     std::chrono::system_clock::now().time_since_epoch().count();
 
-  client_data_shared_ptr->add_new_reply(
+  client_data->add_new_reply(
     std::make_unique<rmw_zenoh_cpp::ZenohReply>(reply, received_timestamp));
 
   // Since we took ownership of the reply, null it out here
   *reply = z_reply_null();
 }
 
+///=============================================================================
+void client_data_drop(void * data)
+{
+  auto client_data = static_cast<rmw_zenoh_cpp::ClientData *>(data);
+  if (client_data == nullptr) {
+    RMW_ZENOH_LOG_ERROR_NAMED(
+      "rmw_zenoh_cpp",
+      "Unable to obtain client_data_t "
+    );
+    return;
+  }
+
+  client_data->decrement_in_flight_and_conditionally_remove();
+}
+
 }  // namespace
 
 namespace rmw_zenoh_cpp
@@ -109,6 +111,7 @@ namespace rmw_zenoh_cpp
 std::shared_ptr<ClientData> ClientData::make(
   z_session_t session,
   const rmw_node_t * const node,
+  const rmw_client_t * client,
   liveliness::NodeInfo node_info,
   std::size_t node_id,
   std::size_t service_id,
@@ -191,6 +194,7 @@ std::shared_ptr<ClientData> ClientData::make(
   std::shared_ptr<ClientData> client_data = std::shared_ptr<ClientData>(
     new ClientData{
       node,
+      client,
       entity,
       request_members,
       response_members,
@@ -203,21 +207,20 @@ std::shared_ptr<ClientData> ClientData::make(
     return nullptr;
   }
 
-  std::lock_guard<std::mutex> lk(client_data_ptr_to_shared_ptr_map_mutex);
-  client_data_ptr_to_shared_ptr_map.emplace(client_data.get(), client_data);
-
   return client_data;
 }
 
 ///=============================================================================
 ClientData::ClientData(
   const rmw_node_t * rmw_node,
+  const rmw_client_t * rmw_client,
   std::shared_ptr<liveliness::Entity> entity,
   const void * request_type_support_impl,
   const void * response_type_support_impl,
   std::shared_ptr<RequestTypeSupport> request_type_support,
   std::shared_ptr<ResponseTypeSupport> response_type_support)
 : rmw_node_(rmw_node),
+  rmw_client_(rmw_client),
   entity_(std::move(entity)),
   request_type_support_impl_(request_type_support_impl),
   response_type_support_impl_(response_type_support_impl),
@@ -225,7 +228,8 @@ ClientData::ClientData(
   response_type_support_(response_type_support),
   wait_set_data_(nullptr),
   sequence_number_(1),
-  is_shutdown_(false)
+  is_shutdown_(false),
+  num_in_flight_(0)
 {
   // Do nothing.
 }
@@ -269,28 +273,28 @@ bool ClientData::init(z_session_t session)
 ///=============================================================================
 liveliness::TopicInfo ClientData::topic_info() const
 {
-  std::lock_guard<std::mutex> lock(mutex_);
+  std::lock_guard<std::recursive_mutex> lock(mutex_);
   return entity_->topic_info().value();
 }
 
 ///=============================================================================
 bool ClientData::liveliness_is_valid() const
 {
-  std::lock_guard<std::mutex> lock(mutex_);
+  std::lock_guard<std::recursive_mutex> lock(mutex_);
   return zc_liveliness_token_check(&token_);
 }
 
 ///=============================================================================
 void ClientData::copy_gid(uint8_t out_gid[RMW_GID_STORAGE_SIZE]) const
 {
-  std::lock_guard<std::mutex> lock(mutex_);
+  std::lock_guard<std::recursive_mutex> lock(mutex_);
   entity_->copy_gid(out_gid);
 }
 
 ///=============================================================================
 void ClientData::add_new_reply(std::unique_ptr<ZenohReply> reply)
 {
-  std::lock_guard<std::mutex> lock(mutex_);
+  std::lock_guard<std::recursive_mutex> lock(mutex_);
   const rmw_qos_profile_t adapted_qos_profile =
     entity_->topic_info().value().qos_;
   if (adapted_qos_profile.history != RMW_QOS_POLICY_HISTORY_KEEP_ALL &&
@@ -324,7 +328,7 @@ rmw_ret_t ClientData::take_response(
   void * ros_response,
   bool * taken)
 {
-  std::lock_guard<std::mutex> lock(mutex_);
+  std::lock_guard<std::recursive_mutex> lock(mutex_);
   *taken = false;
 
   if (is_shutdown_ || reply_queue_.empty()) {
@@ -389,7 +393,7 @@ rmw_ret_t ClientData::send_request(
   const void * ros_request,
   int64_t * sequence_id)
 {
-  std::lock_guard<std::mutex> lock(mutex_);
+  std::lock_guard<std::recursive_mutex> lock(mutex_);
   if (is_shutdown_) {
     return RMW_RET_OK;
   }
@@ -468,7 +472,7 @@ rmw_ret_t ClientData::send_request(
   // TODO(Yadunund): Once we switch to zenoh-cpp with lambda closures,
   // capture shared_from_this() instead of this.
   z_owned_closure_reply_t zn_closure_reply =
-    z_closure(client_data_handler, nullptr, this);
+    z_closure(client_data_handler, client_data_drop, this);
   z_get(
     context_impl->session(),
     z_loan(keyexpr_), "",
@@ -481,11 +485,6 @@ rmw_ret_t ClientData::send_request(
 ///=============================================================================
 ClientData::~ClientData()
 {
-  {
-    std::lock_guard<std::mutex> lk(client_data_ptr_to_shared_ptr_map_mutex);
-    client_data_ptr_to_shared_ptr_map.erase(this);
-  }
-
   const rmw_ret_t ret = this->shutdown();
   if (ret != RMW_RET_OK) {
     RMW_ZENOH_LOG_ERROR_NAMED(
@@ -501,7 +500,7 @@ void ClientData::set_on_new_response_callback(
   rmw_event_callback_t callback,
   const void * user_data)
 {
-  std::lock_guard<std::mutex> lock(mutex_);
+  std::lock_guard<std::recursive_mutex> lock(mutex_);
   data_callback_mgr_.set_callback(user_data, std::move(callback));
 }
 
@@ -509,7 +508,7 @@ void ClientData::set_on_new_response_callback(
 bool ClientData::queue_has_data_and_attach_condition_if_not(
   rmw_wait_set_data_t * wait_set_data)
 {
-  std::lock_guard<std::mutex> lock(mutex_);
+  std::lock_guard<std::recursive_mutex> lock(mutex_);
   if (!reply_queue_.empty()) {
     return true;
   }
@@ -521,19 +520,17 @@ bool ClientData::queue_has_data_and_attach_condition_if_not(
 ///=============================================================================
 bool ClientData::detach_condition_and_queue_is_empty()
 {
-  std::lock_guard<std::mutex> lock(mutex_);
+  std::lock_guard<std::recursive_mutex> lock(mutex_);
   wait_set_data_ = nullptr;
 
   return reply_queue_.empty();
 }
 
 ///=============================================================================
-rmw_ret_t ClientData::shutdown()
+void ClientData::_shutdown()
 {
-  rmw_ret_t ret = RMW_RET_OK;
-  std::lock_guard<std::mutex> lock(mutex_);
   if (is_shutdown_) {
-    return ret;
+    return;
   }
 
   // Unregister this node from the ROS graph.
@@ -545,13 +542,41 @@ rmw_ret_t ClientData::shutdown()
   }
 
   is_shutdown_ = true;
+}
+
+///=============================================================================
+rmw_ret_t ClientData::shutdown()
+{
+  std::lock_guard<std::recursive_mutex> lock(mutex_);
+  _shutdown();
   return RMW_RET_OK;
 }
 
+///=============================================================================
+bool ClientData::shutdown_and_query_in_flight()
+{
+  std::lock_guard<std::recursive_mutex> lock(mutex_);
+  _shutdown();
+  return num_in_flight_ > 0;
+}
+
+///=============================================================================
+void ClientData::decrement_in_flight_and_conditionally_remove()
+{
+  std::lock_guard<std::recursive_mutex> lock(mutex_);
+  --num_in_flight_;
+
+  if (is_shutdown_ && num_in_flight_ == 0) {
+    rmw_context_impl_s * context_impl = static_cast<rmw_context_impl_s *>(rmw_node_->data);
+    std::shared_ptr<rmw_zenoh_cpp::NodeData> node_data = context_impl->get_node_data(rmw_node_);
+    node_data->delete_client_data(rmw_client_);
+  }
+}
+
 ///=============================================================================
 bool ClientData::is_shutdown() const
 {
-  std::lock_guard<std::mutex> lock(mutex_);
+  std::lock_guard<std::recursive_mutex> lock(mutex_);
   return is_shutdown_;
 }
 }  // namespace rmw_zenoh_cpp
diff --git a/rmw_zenoh_cpp/src/detail/rmw_client_data.hpp b/rmw_zenoh_cpp/src/detail/rmw_client_data.hpp
index cee312b1..eda4bf9c 100644
--- a/rmw_zenoh_cpp/src/detail/rmw_client_data.hpp
+++ b/rmw_zenoh_cpp/src/detail/rmw_client_data.hpp
@@ -49,6 +49,7 @@ class ClientData final : public std::enable_shared_from_this<ClientData>
   static std::shared_ptr<ClientData> make(
     z_session_t session,
     const rmw_node_t * const node,
+    const rmw_client_t * client,
     liveliness::NodeInfo node_info,
     std::size_t node_id,
     std::size_t service_id,
@@ -79,22 +80,27 @@ class ClientData final : public std::enable_shared_from_this<ClientData>
     const void * ros_request,
     int64_t * sequence_id);
 
+  // Set a callback to be called when events happen.
   void set_on_new_response_callback(
     rmw_event_callback_t callback,
     const void * user_data);
 
-  // rmw_wait helpers.
+  // Check if there is data in the queue, and if not attach the wait set condition variable.
   bool queue_has_data_and_attach_condition_if_not(
     rmw_wait_set_data_t * wait_set_data);
 
+  // Detach any attached wait set condition variable, and return whether there is data in the queue.
   bool detach_condition_and_queue_is_empty();
 
-  // See the comment for "num_in_flight" below on the use of this method.
-  void decrement_queries_in_flight();
-
   // Shutdown this ClientData.
   rmw_ret_t shutdown();
 
+  // Shutdown this ClientData, and return whether there are any requests currently in flight.
+  bool shutdown_and_query_in_flight();
+
+  // Decrement the in flight requests, and if that drops to 0 remove the client from the node.
+  void decrement_in_flight_and_conditionally_remove();
+
   // Check if this ClientData is shutdown.
   bool is_shutdown() const;
 
@@ -105,6 +111,7 @@ class ClientData final : public std::enable_shared_from_this<ClientData>
   // Constructor.
   ClientData(
     const rmw_node_t * rmw_node,
+    const rmw_client_t * client,
     std::shared_ptr<liveliness::Entity> entity,
     const void * request_type_support_impl,
     const void * response_type_support_impl,
@@ -114,10 +121,14 @@ class ClientData final : public std::enable_shared_from_this<ClientData>
   // Initialize the Zenoh objects for this entity.
   bool init(z_session_t session);
 
+  // Shutdown this client (the mutex is expected to be held by the caller).
+  void _shutdown();
+
   // Internal mutex.
-  mutable std::mutex mutex_;
+  mutable std::recursive_mutex mutex_;
   // The parent node.
   const rmw_node_t * rmw_node_;
+  const rmw_client_t * rmw_client_;
   // The Entity generated for the service.
   std::shared_ptr<liveliness::Entity> entity_;
   // An owned keyexpression.
@@ -139,6 +150,7 @@ class ClientData final : public std::enable_shared_from_this<ClientData>
   size_t sequence_number_;
   // Shutdown flag.
   bool is_shutdown_;
+  size_t num_in_flight_;
 };
 using ClientDataPtr = std::shared_ptr<ClientData>;
 using ClientDataConstPtr = std::shared_ptr<const ClientData>;
diff --git a/rmw_zenoh_cpp/src/detail/rmw_node_data.cpp b/rmw_zenoh_cpp/src/detail/rmw_node_data.cpp
index f3430280..bd3f3f6e 100644
--- a/rmw_zenoh_cpp/src/detail/rmw_node_data.cpp
+++ b/rmw_zenoh_cpp/src/detail/rmw_node_data.cpp
@@ -347,6 +347,7 @@ bool NodeData::create_client_data(
   auto client_data = ClientData::make(
     std::move(session),
     node_,
+    client,
     entity_->node_info(),
     id_,
     std::move(id),
@@ -387,10 +388,9 @@ void NodeData::delete_client_data(const rmw_client_t * const client)
   if (client_it == clients_.end()) {
     return;
   }
-  // Shutdown the client, then erase it.  The code in rmw_client_data.cpp is careful about keeping
-  // it alive as long as necessary.
-  client_it->second->shutdown();
-  clients_.erase(client);
+  if (!client_it->second->shutdown_and_query_in_flight()) {
+    clients_.erase(client);
+  }
 }
 
 ///=============================================================================