The design and optimization of a gas-to-liquids technology (GTL) is considered, mostly from the view of an optimal choice of a synthesis gas (syngas) production method. Material balance and energy efficiency are calculated for a number of flowsheets, which comprise syngas production by various techniques and Fischer-Tropsch (FT) synthesis of liquid hydrocarbons (LHs). Three different methods are considered for syngas production: combined steam and dry reforming; autothermal reforming; and partial oxidation. The FT process is considered in the version, which produces LHs, not waxes. The results of modeling manifest that the choice of syngas production method influences dramatically the efficiency of overall GTL technology. Ways to improve the efficiency of GTL technology are discussed.