A process for preparing a cobalt based catalyst precursor includes in a first support impregnation/drying/calcination stage, impregnating a particulate porous catalyst support with a cobalt salt, partially drying the impregnated support, and calcining the partially dried impregnated support to obtain a calcined material. The calcined material is partially reduced. Thereafter, in a second support impregnation/drying/calcination stage, the partially reduced material is impregnated with a cobalt salt, partially dried and calcined, to obtain the cobalt based catalyst precursor.