A new turbocharger series for the engine with 400-2000 kW per turbocharger has been designed by IHI for world wide usage. There are 4 frame sizes, with two models per frame size.The new features for this size turbocharger include; (1) A twin scroll mixed flow turbine which has been adopted for effective utilization of exhaust pulse energy from engine. (2) A newly designed compressor stage that features higher pressure ratio as well as improved compressor stability at partial load. (3) Full floating journal bearings which are adopted to achieve good dynamic stability as well as good mechanical efficiency. The reliability and component characteristics have been evaluated on IHI's test bench as well as on engines. A bearing test stand was developed to evaluate the durability of bearing system. By driving the compressor with compressed air and heating the turbine casing, actual turbocharger operating conditions, can be simulated.The RH..3 turbocharger series is now in production for various 4-stroke diesel and gas engines.In this paper, the authors describe the RH..3 series structural features as well as reliability, characteristic and engine test results.