The article presents an overview of methods for the production of bioethanol and the possibility of its use to power internalcombustion engines. The effects of supplying spark-ignition engine with bioethanol having various degrees of hydration were examined experimentally on the engine dynamometer. The measurement results were referred to the anhydrous bioethanol, which is used widely as petrol biocomponent and compared in terms of the course of the pressure in the combustion chamber of the engine as well as engine performance parameters – torque and power. It was found that with the decrease in alcohol concentration, the performance of the sparkignition engine deteriorated. The reduction of in-cylinder pressure was proportional to the increase in the water content in the fuel. No significant changes in the general shape of in-cylinder pressure curves were observed. Engine torque and power decreased with an increase in the water content in the fuel, especially at high engine speed. It has been stated that supplying the engine with bioethanol containing up to 6% (v/v) of water does not result in significant losses in engine performance.