The partial oxidation and CO2 reforming of coke oven gas (COG) to syngas was investigated on differently sized Ni catalysts in a fluidized-bed reactor. It was found that the catalytic performance of Ni depends strongly on its particle size. The small-sized Ni catalyst exhibited higher activity and higher selectivity in the partial oxidation of COG. The conversion of CH4 was kept at 80.7% at a lower temperature (750 degrees C) and a wide space velocity (from 8000 to 80 000 h(-1)). CO2 reforming of COG is also an efficient route for syngas production. The H-2/CO ratio in the COG-derived syngas could be controlled by manipulating the concentration of O-2 or CO2 added in the feed. The yield of produced syngas increases with an increase in temperature.