The aim of this study is to develop a computer-controlled, hydraulically actuated system for oval turning of internal combustion engine pistons by using conventional lathes. An encoder is mounted on the spindle to generate a synchronization signal. A reference signal which is in phase with the synchronization signal is generated by a computer. The system which controls the cutting tool position consists of a computer, a data acquisition and control board, a hydraulic cylinder, a servovalve, a servoamplifier and a position transducer. A base block which carries the hydraulic cylinder, transducer, servovalve and the cutting tool block mounted on a balled slide bearing is placed on top of carriage. The system actuates the cutting tool in synchronization with the spindle rotation and produces oval shaped parts at normal operating speeds. Experiments are carried out on a TEZSAN MAS165 model universal lathe at various speeds up to the maximum available speed of 1620 rpm. The amounts of ovality obtained from the experiments are found to be satisfactory for piston requirements.