A method is provided for converting synthesis gas to liquid hydrocarbon mixtures useful as distillate fuel and/or lube base oil. The synthesis gas is contacted with a synthesis gas conversion catalyst comprising a Fischer-Tropsch synthesis component in an upstream catalyst bed thereby producing an intermediate hydrocarbon mixture containing olefins and C21+ normal paraffins. The intermediate hydrocarbon mixture is subsequently contacted with a hydroisomerization catalyst and an olefin saturation catalyst, thereby resulting in a product containing no greater than about 25 wt % olefins and containing no greater than about 5 wt % C21+ normal paraffins. The hydroisomerization and olefin saturation catalysts may be in separate beds or mixed in a single bed downstream of the synthesis gas conversion catalyst.