In all the world mopeds and motorcycles are popular means of daily moving, helping to meet daily urban transport needs, as a consequence two-wheelers contribution to air pollution is generally significant, especially in urban environment. Emission models commonly used in Europe, are based mainly on the average trip speed to predict emissions, thus they are not sensitive to variations of vehicles instantaneous speed and acceleration, which have a strong effect on emissions and fuel consumption; besides these models do not analyze in depth the cold emissive behavior of motorcycles. An expansion of the two-wheelers emission database was deemed necessary.This study is aimed at the examination of the emissions of in-use motorcycles during real driving conditions, contributing significantly to extend the knowledge of two-wheeler emission behavior. For this purpose, an experimental investigation was realized by the Department of Mechanic and Energetic (DiME) of the University of Naples: emissions of regulated pollutants (CO, HC and NOX) were evaluated in the exhaust of one scooter belonging to the Euro-3 legislative category, equipped with catalytic converter, and with a displacement of 300 cm₃. In order to evaluate the performance of this motorcycle under real-world motorcycle riding, in cold and hot conditions, sampling was achieved on a dynamometer bench during both the Type Approval driving cycle and real-world driving cycles, also by employing the instantaneous emission results. The experimental data and the statistical processing results of this research are compared with current emission models for calculating emissions from road traffic.