Registered vehicles in Thailand, are currently required to pass the European standard (EURO3) driving cycle. Motorcycles comprise the registered vehicles in Thailand, thus it is important to study the exhaust emissions of motorcycles tested with both the European standard driving cycle: Hot emission (EURO3H) and the Bangkok driving cycle. The Bangkok driving cycle has been developed to represent Bangkok traffic. This was a study of gasoline motorcycles with three-way catalytic converters installed to investigate the exhaust emissions using a chassis dynamometer test to compare the EURO3H with the Bangkok driving cycle. The comparison of idle time, velocity and emissions of Carbon Monoxide (CO), Nitrogen Oxide (NOx) and Total Hydrocarbon (THC) for the EURO3H and 6 different phases of the Bangkok driving cycle were investigated. The results showed the emissions of CO and NOx were higher for all phases of the Bangkok driving cycle due to a lesser proportion of idle time and a greater proportion of high average velocity. For example, even though the idle time ratio of the EURO3H was almost at the same level as that of phase 2 of the Bangkok driving cycle, it effected a higher level of CO and THC owing to a lesser proportion of high average velocity.