The effects of using blends of unleaded gasoline and refined fusel oil on engine performance and exhaust emissions were analyzed. Prior to the experiment, the fusel oil, which is the final waste product of the sugar factory, was developed to have the chemical properties that can be used in internal combustion engines by removing water and gum contained therein. A four-stroke, single-cylinder, spark-ignition engine was used for the experiments. The tests were conducted at a fixed speed and under different loads. The test fuels were blended with fusel oil contents of 5%, 15%, and 30%. Under each load, the engine's performance and emissions were measured. Throughout the experiments, it was observed that engine torque and fuel consumption increased as the amount of fusel oil in the blend increased. Nitrogen oxide (NOx), carbon monoxide (CO), and hydrocarbon (HC) emissions were reduced as the amount of fusel oil in the blends increased.