diff --git a/behaviortree_ros2/include/behaviortree_ros2/bt_topic_sub_node.hpp b/behaviortree_ros2/include/behaviortree_ros2/bt_topic_sub_node.hpp
index 4a97079..65c2196 100644
--- a/behaviortree_ros2/include/behaviortree_ros2/bt_topic_sub_node.hpp
+++ b/behaviortree_ros2/include/behaviortree_ros2/bt_topic_sub_node.hpp
@@ -26,7 +26,14 @@
 
 namespace BT
 {
-
+/**
+ * @brief Settings for how the subscriber should read messages
+ * 
+ * READ_ONCE: Read the message once then clear it
+ * READ_LATCH: Keep reading the same message until a new one is received
+ * READ_CONFIGURABLE: Read the message once then clear it, unless the "read_last" port is set to true 
+ */
+enum class SubscriberReadMode { READ_ONCE, READ_LATCH, READ_CONFIGURABLE };
 
 /**
  * @brief Abstract class to wrap a Topic subscriber.
@@ -35,14 +42,17 @@ namespace BT
  *
  * The corresponding wrapper would be:
  *
- * class SubscriberNode: RosTopicSubNode<std_msgs::msg::String>
+ * class SubscriberNode: RosTopicSubNode<std_msgs::msg::String, SubscriberReadMode::READ_ONCE>
  *
  * The name of the topic will be determined as follows:
  *
  * 1. If a value is passes in the InputPort "topic_name", use that
  * 2. Otherwise, use the value in RosNodeParams::default_port_value
+ * 
+ * To configure the reading mode, set the 2nd class template parameter to one of the options in SubscriberReadMode.
+ * If not set READ_ONCE will be used by default for backwards compatibility.
  */
-template<class TopicT>
+template<class TopicT, SubscriberReadMode read_mode = SubscriberReadMode::READ_ONCE>
 class RosTopicSubNode : public BT::ConditionNode
 {
  public:
@@ -132,6 +142,13 @@ class RosTopicSubNode : public BT::ConditionNode
     PortsList basic = {
       InputPort<std::string>("topic_name", "__default__placeholder__", "Topic name")
     };
+    if (read_mode == SubscriberReadMode::READ_CONFIGURABLE)
+    {
+      basic.insert(InputPort<bool>(
+        "read_last",
+        false,
+        "Read mode. True if read last message, even if it has already been seen. False if read only new messages."));
+    }
     basic.insert(addition.begin(), addition.end());
     return basic;
   }
@@ -165,8 +182,8 @@ class RosTopicSubNode : public BT::ConditionNode
 //---------------------- DEFINITIONS -----------------------------
 //----------------------------------------------------------------
 
-template<class T> inline
-  RosTopicSubNode<T>::RosTopicSubNode(const std::string & instance_name,
+template<class T, SubscriberReadMode read_mode = SubscriberReadMode::READ_ONCE> inline
+  RosTopicSubNode<T, read_mode>::RosTopicSubNode(const std::string & instance_name,
                                       const NodeConfig &conf,
                                       const RosNodeParams& params)
     : BT::ConditionNode(instance_name, conf),
@@ -211,8 +228,8 @@ template<class T> inline
   }
 }
 
-template<class T> inline
-  bool RosTopicSubNode<T>::createSubscriber(const std::string& topic_name)
+template<class T, SubscriberReadMode read_mode> inline
+  bool RosTopicSubNode<T, read_mode>::createSubscriber(const std::string& topic_name)
 {
   if(topic_name.empty())
   {
@@ -247,8 +264,8 @@ template<class T> inline
 }
 
 
-template<class T> inline
-  NodeStatus RosTopicSubNode<T>::tick()
+template<class T, SubscriberReadMode read_mode> inline
+  NodeStatus RosTopicSubNode<T, read_mode>::tick()
 {
   // First, check if the subscriber_ is valid and that the name of the
   // topic_name in the port didn't change.
@@ -271,7 +288,11 @@ template<class T> inline
   };
   sub_instance_->callback_group_executor.spin_some();
   auto status = CheckStatus (onTick(last_msg_));
-  last_msg_ = nullptr;
+  if (read_mode == SubscriberReadMode::READ_ONCE ||
+    (read_mode == SubscriberReadMode::READ_CONFIGURABLE && !getInput<bool>("read_last").value()))
+  {
+    last_msg_ = nullptr;
+  }
 
   return status;
 }