The European Automotive Industry is facing the challenge to reduce the CO2 emissions in the NEDC to 140 g/km in year 2008 and to 120 g/km in year 2010. In order to comply with those requirements, the introduction of fuel-efficient technologies is mandatory. Downsizing is a known way to reduce part load fuel consumption by combining significant displacement reduction with turbocharging, to achieve equivalent torque and power levels. The review of contemporary applied downsizing systems for combustion engines has been presented in article. The technical data of the chosen newest vehicles with downsizing systems have been also compared.