This invention concerns a process for the catalytic partial oxidation of a hydrocarbon feedstock. The process comprises contacting a feed mixture comprising the hydrocarbon feedstock and an oxygen-containing gas, which feed mixture also comprises nitrogen, with a catalyst capable of catalyzing the partial oxidation of the hydrocarbon feedstock, wherein the feed mixture also comprises a sulfur-containing compound. This process allows sulfur-containing hydrocarbon feedstocks to be processed without first undergoing a sulfur removal treatment. Accordingly, a process for the preparation of carbon monoxide and/or hydrogen from a hydrocarbon feedstock comprises subjecting the hydrocarbon feedstock in a first stage to a catalytic partial oxidation process as described above and subjecting at least a portion of the product of the first stage in a second stage to a desulfurization process.