These proceedings of the 4th International Conference on Mechanical and Electrical Technology (ICMET 2012), held during the 24 to 26th July 2012 in Kuala Lumpur, Malaysia, take the form of 614 peer-reviewed papers grouped as follows: Materials Engineering; Applied Mechanics and Mechanical Engineering; Electrotechnics and Electrical Machines; Energy and Power Engineering; Measurements, Monitoring and Sensors; Electronic and Radio Engineering; Computer-Aided Design and Technology; Control and Automation; Manufacturing Processes and Technology.