This paper reports the results of an experimental study involving Fischer-Tropsch synthesis on Co/SiO2-Al2O3 catalyst. The objective of the study was to find the reaction conditions for achieving an optimal selectivity with respect to C-5(+)-liquid hydrocarbons. The experimental data on reaction conversion and steady-state concentrations of different product species has been used to develop artificial neural-network-based models which are generic and can be used for predicting the reaction behaviour under different operating conditions.