Taking into account these considerations, a reliable evaluation of the emissive behavior of motorcycles in hot and cold conditions is of the greatest importance. Consequently, an experimental investigation focusing on these issues was carried out by the Department of Industrial Engineering of the University of Naples Federico on the basis of roller test bench measurements. Emissions of regulated pollutants (CO, HC and NOX) were evaluated in the exhaust of two high performance motorcycles of 1,000 cm 3 swept volume, belonging to the Euro-3 legislative category. The tested vehicles were selected for similar engine and after-treatment system characteristics, thus allowing a comparison between them, and are equipped with sophisticated devices for improving combustion efficiency, and the abatement of exhaust pollutants. These vehicles are representative of the newly sold high-performance motorcycles that in the last years are very used also in urban environment and then play a growing central role in private mobility.