conversion of so-called synthesis gas, composed mainly of carbon monoxide and hydrogen, to hydrocarbons (hydrocarbon) through the influence of elevated temperatures and normal or elevated pressures in the presence of a catalyst of magnetic iron oxide.

The process was first used in Germany about 1940 as a method of producing liquid and gaseous hydrocarbon fuels, such as gasoline or gas oil, and is named after the German chemists Franz Fischer and Hans Tropsch.