A series of C-supported Co catalysts (Co(2, 5 and 8wt%)/C) were prepared by impregnation. The effects of Co loading amounts and reaction temperature on ethanol decomposition to produce hydrogen and carbon nanotubes (CNTs) were investigated systematically. The results indicate that Co/C was quite an active catalyst for the co-production of hydrogen and CNTs at a relatively low temperature of 500°C. Of all the catalysts, Co(5wt%)/C was the most effective one based on the high hydrogen yield (88%) and CNT quality (being of relatively higher purity and lower defects). Besides H 2 , CO, CH 4 and CO 2 were also produced and the selectivity of the gas was in the order H 2 >CO>CO 2 >CH 4 .