The new requirements for sulfur content in liquid fuels demand the use of novel deep desulfurization processes. 4-methyldibenzothiophene, 4,6-dimethyldibenzothiophene and their alkyl-substituted derivatives are the key substances that need to be separated from diesel fuel and fuel oil. These compounds require higher hydrogen consumption in the hydrodesulfurization process and the use of additional infrastructure in the treatment facility. The common hydrogenation catalysts are not very effective for the hydro-genization of these compounds, and new innovation for catalysts is required. The desulfurization of fuel oil obtained front oil shale is also becoming important and has different technological needs than other fuels. This paper critically discusses the non-hydrodesulfurization processes for liquid fuels, such as extraction, oxidation, and adsorption. These processes, their development, and recent advances in this research field are briefly evaluated as possible deep desulfurization methods.