The combination of CO/CO2 shift reactions with Fischer-Tropsch synthesis offers the possibility to produce hydrocarbons from CO-rich syngas (from biomass or coal gasification) and from H-2/CO2 mixtures. In the case of CO-rich synthesis gas, the H-2/CO ratio needs to meet stoichiometric requirements for the low-temperature Fischer-Tropsch synthesis and therefore the CO is shifted to CO2 to form additional H-2. Mixtures of H-2/CO2 require the shift of CO2 into CO, which acts as intermediate in the production of short-chain hydrocarbons via high-temperature Fischer-Tropsch synthesis. The present work analyzes based on validated kinetic models how the shift reaction affects the FT reaction under operation conditions of interest and how both FT and shift reactions can be optimized to maximize hydrocarbon production. (C) 2013 Elsevier B.V. All rights reserved.