Liquid fuels contribute a significant share to the energy supply of modern societies, primarily in the transportation sector and for heating purposes. They will remain important even after heat demands of buildings have decreased significantly and electrical drive systems for passenger cars have become important. The main reason for this is the high energy density which is of major importance in mobile applications. Today's predominant raw material petroleum will be complemented and replaced for reasons of price increase, supply security, and fossil CO(2) emissions. This paper summarizes recent developments regarding the production of substitutes for petroleum-derived liquid fuels, in particular of synthetic fuels from natural gas and biomass. Criteria for discussion are chemical principles, process technology, energy efficiency and production cost.