This paper reports the application of fractional factorial technique in the design and selection of an optimal K-promoted Co-Mo catalyst system for hydrocarbon production from CO hydro enation. Catalyst samples were prepared via incipient wetness impregnation and evaluated using a syngas mixture with H-2/CO=2 at 101 kPa and 553 K in a fixed bed reactor. Characterisation data from TGA, XRD, TEM-EDS and XPS showed that the formation of new phases between Co and Mo oxides was practically non-existent. Inferences from statistical analysis, qualitative rate data interpretation and modelling exercise all suggest that K and Co are required for both activity and selectivity. Mo, however, inhibited the overall synthesis rate but significantly improved alkene selectivity, due to methane suppression. Increased calcination temperature (within the range 573-723 K) enhanced BET surface area, but was deleterious to both activity and selectivity.