A process for preparing a cobalt-based Fischer-Tropsch synthesis catalyst includes introducing a soluble modifying component precursor of the formula Mc(OR).sub.x, where Mc is a modifying component selected from the group comprising Si, Ti, Cu, Zn, Zr, Mn, Ba, Ni, Na, K, Ca, Sn, Cr, Fe, Li, Tl, Sr, Ga, Sb, V, Hf, Th, Ce, Ge, U, Nb, Ta, W or La, R is an alkyl or acyl group, and x is an integer having a value of from 1 to 5, onto and/or into a cobalt-based Fischer-Tropsch synthesis catalyst precursor, which comprises a porous pre-shaped catalyst support supporting cobalt in an oxidized form. The resultant modified cobalt-based Fischer-Tropsch synthesis catalyst precursor is reduced to obtain a cobalt-based Fischer-Tropsch synthesis catalyst.