Abstarct: Driving cycle is one of the most important parameters affecting the emission of air pollutants. Driving cycle is the movement pattern of vehicles in urban routes and is introduced by speed-time charts. The driving pattern in Mashhad is different due to cultural differences in the use of vehicles. The behavior of drivers can have a big impact on the driving cycle leading to changes in the prediction of pollutant emissions. In this thesis, instead of using traffic software, the on-board driving pattern was obtained for urban vehicles. First, the speed-time data of the vehicle was obtained in two weeks in the morning and afternoon traffic peak hours and a non-peak time in two different routes by GPS. Thereafter, the microtrips were obtained for all speed-time data and the driving cycle was developed by random combination of microtrips. The error for the developed driving cycle was about 2 percent reflecting the high accuracy of this method. The driving cycle of Mashhad was compared with standard driving cycles in Europe and America. After development of the driving cycle, vehicle exhaust emissions were estimated by the The International Vehicle Emissions (IVE) model. In order to correct the emissions obtained from the IVE model, on-board vehicle emissions were obtained. Then, for each of the emission factors, the correction factors were added to the IVE model. The emission factors obtained for Mashhad were compared with those reported for Beijing, Pune and Mexico. The driving cycle of Mashhad showed that the average speed in Mashhad is significantly different with that in the European and American driving cycles. The idle time percentage in Mashhad was close to that in the European driving cycle, but is different from the American driving cycle. The results of the IVE model showed that carbon monoxide from vehicle exhausts constituted the most emission among standard pollutant emissions. Ammonia and benzene were the main toxic gases in vehicle exhaust, respectively. Comparison of the vehicle exhaust emission factors in Mashhad with Beijing, Pune and Mexico showed that carbon monoxide is the main exhaust emission in Mashhad driving cycle as compared with other three regions.