Cobalt catalysts supported on mesoporous silica for Fischer-Tropsch synthesis were prepared by supercritical CO2 at 333K, 20 MPa with an addition of 10 mol% methanol. Highly dispersed Co particles in mesopores could be observed by TEM for the sample by supercritical CO2 method, while the aggregates of Co particles on external surface of silica were found for the conventional liquid phase impregnation method. Fischer-Tropsch synthesis examined at 503K, 1.1 MPa revealed CO conversion to be 46.7% using the catalyst prepared by supercritical CO2 method, which was about 1.5 times higher than the catalyst prepared by the conventional method. (c) 2015 The Institution of Chemical Engineers. Published by Elsevier BAT. All rights reserved.