The invention concerns a process for preparing a chlorine comprising catalyst by (a) providing a Fischer-Tropsch catalyst comprising titania and at least 5 weight percent cobalt; (b) impregnating the catalyst with a solution comprising chloride ions; and (c) heating the impregnated catalyst at a temperature in the range of between 100 and 500° C. for at least 5 minutes up to 2 days. The prepared catalyst preferably comprises 0.13-3 weight percent of the element chlorine. The invention further relates to the prepared catalyst and its use.