In this study, the effects of unleaded gasoline, ethanol-gasoline (E5, E10) and methanol-gasoline (M5, M10) blends on combustion characteristics and exhaust emissions were investigated experimentally. In the experiments, a vehicle which has a four-cylinder and four-stroke spark ignition engine was used. The experiments were performed at 80 km/h vehicle speeds and 5, 10, 15, 20 kW constant vehicle power by using a chassis dynamometer. The results obtained from E5, E10, M5 and M10 were compared with the reference unleaded gasoline fuel. At the end of the experiments, it was seen that the brake specific fuel consumptions of ethanol-gasoline and methanol-gasoline blends were increased. The increase in the cylinder gas pressure and heat release rate of gasoline were started earlier than alcohol-gasoline blends. Almost in the all test conditions, the lowest peak heat release rate was obtained in the gasoline fuel use. Moreover, when the alcohol blends were used in the engine, it was generally seen that CO, HC, CO(2) and NO(x) emissions decreased.