diff --git a/diagnostic_common_diagnostics/CMakeLists.txt b/diagnostic_common_diagnostics/CMakeLists.txt
index 43202b9e..42ad3e4e 100644
--- a/diagnostic_common_diagnostics/CMakeLists.txt
+++ b/diagnostic_common_diagnostics/CMakeLists.txt
@@ -10,6 +10,7 @@ ament_python_install_package(${PROJECT_NAME})
 install(PROGRAMS
     ${PROJECT_NAME}/cpu_monitor.py
     ${PROJECT_NAME}/ntp_monitor.py
+    ${PROJECT_NAME}/ram_monitor.py
     DESTINATION lib/${PROJECT_NAME}
 )
 
diff --git a/diagnostic_common_diagnostics/README.md b/diagnostic_common_diagnostics/README.md
index 95e41627..e0d75ab1 100644
--- a/diagnostic_common_diagnostics/README.md
+++ b/diagnostic_common_diagnostics/README.md
@@ -56,7 +56,27 @@ Disable self test.
 **To be ported**
 
 ## ram_monitor.py
-**To be ported**
+The `ram_monitor` module allows users to monitor the RAM usage of their system in real-time.
+It publishes the usage percentage in a diagnostic message.
+
+* Name of the node is "ram_monitor_" + hostname.
+* Uses the following args:
+  * warning_percentage: If the RAM usage is > warning_percentage, a WARN status will be published.
+  * window: the maximum length of the used collections.deque for queuing CPU readings.
+
+### Published Topics
+#### /diagnostics
+diagnostic_msgs/DiagnosticArray
+The diagnostics information.
+
+### Parameters
+#### warning_percentage
+(default: 90)
+warning percentage threshold.
+
+#### window
+(default: 1)
+Length of RAM readings queue.
 
 ## sensors_monitor.py
 **To be ported**
diff --git a/diagnostic_common_diagnostics/diagnostic_common_diagnostics/ram_monitor.py b/diagnostic_common_diagnostics/diagnostic_common_diagnostics/ram_monitor.py
new file mode 100755
index 00000000..15897cb6
--- /dev/null
+++ b/diagnostic_common_diagnostics/diagnostic_common_diagnostics/ram_monitor.py
@@ -0,0 +1,84 @@
+#!/usr/bin/env python
+#
+# Software License Agreement (BSD License)
+#
+# Copyright (c) 2017, TNO IVS, Helmond, Netherlands
+# All rights reserved.
+#
+# Redistribution and use in source and binary forms, with or without
+# modification, are permitted provided that the following conditions
+# are met:
+#
+#  * Redistributions of source code must retain the above copyright
+#    notice, this list of conditions and the following disclaimer.
+#  * Redistributions in binary form must reproduce the above
+#    copyright notice, this list of conditions and the following
+#    disclaimer in the documentation and/or other materials provided
+#    with the distribution.
+#  * Neither the name of the TNO IVS nor the names of its
+#    contributors may be used to endorse or promote products derived
+#    from this software without specific prior written permission.
+#
+# THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
+# "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
+# LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS
+# FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE
+# COPYRIGHT OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT,
+# INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING,
+# BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
+# LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER
+# CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
+# LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN
+# ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
+# POSSIBILITY OF SUCH DAMAGE.
+
+# \author Rein Appeldoorn
+
+import collections
+import socket
+
+import psutil
+import rclpy
+from diagnostic_msgs.msg import DiagnosticStatus
+from diagnostic_updater import DiagnosticTask, Updater
+
+
+class RamTask(DiagnosticTask):
+    def __init__(self, warning_percentage, window=1):
+        DiagnosticTask.__init__(self, "RAM Information")
+        self._warning_percentage = int(warning_percentage)
+        self._readings = collections.deque(maxlen=window)
+
+    def run(self, stat):
+        self._readings.append(psutil.virtual_memory().percent)
+        ram_average = sum(self._readings) / len(self._readings)
+
+        stat.add("RAM Load Average", "{:.2f}".format(ram_average))
+
+        if ram_average > self._warning_percentage:
+            stat.summary(DiagnosticStatus.WARN,
+                         "RAM Average exceeds {:d} percent".format(self._warning_percentage))
+        else:
+            stat.summary(DiagnosticStatus.OK, "RAM Average {:.2f} percent".format(ram_average))
+
+        return stat
+
+
+def main():
+    hostname = socket.gethostname()
+    rclpy.init()
+    node = rclpy.create_node('ram_monitor_%s' % hostname.replace("-", "_"))
+
+    updater = Updater(node)
+    updater.setHardwareID(hostname)
+    updater.add(
+        RamTask(node.declare_parameter("warning_percentage", 90.0).value, node.declare_parameter("window", 1).value))
+
+    rclpy.spin(node)
+
+
+if __name__ == '__main__':
+    try:
+        main()
+    except KeyboardInterrupt as e:
+        pass