Oxidative desulfurization is a process in which sulfur compounds are being oxidized and removed from diesel fuels. Sulfur compounds are undesirable because they are catalytic poisons, they are highly corrosive in crude oil processing and they create very environmentally damaging acid gases. It is necessary to continuously improve the quality of motor fuels, primarily towards reduction of sulfur content in diesel fuels which can be achieved by various methods of desulfurization. Hydrodesulfurization is the most common desulfurization technology. The process of oxidative desulfurization (ODS) has been developed as an alternative to the process of hydrodesulfurization (HDS). Advantages are mild reaction conditions, atmospheric pressure and temperatures up to 100 °C and no hydrogen usage. Another important advantage of ODS is oxidizing thiophenic compounds to sulfoxides and sulfones, that can be easily removed by extraction or adsorption process. The effect of surface – active agents, time, temperature, the ratio of oxidant and catalyst and the power of ultrasound on the process of oxidative desulfurization of model diesel fuel was researched in this work. Experiments were conducted with hydrogen peroxide as oxidant and acetic acid as catalyst. After the oxidation, the process of extraction with dimethyl formamide was conducted, which proved to be the best solvent. The results indicate that the oxidative desulfurization process can also be improved by using ultrasound irradiation combined with using surface – active agents, at a lower temperature and a shorter time.