On the ground that the sulphonamide group of drugs after suitable synthetic modifications of their molecules may probably be useful in mycobacterial infections, the possibility of rendering a few members, previously known to be active in coccal infections, lipophilic by the introduction of fatty acid residues in the latter has been explored. Accordingly, normal and branched chain acyl derivatives, thirty-seven in all, of sulphanilamide, sulphapyridine, sulphathiazole, sulphathiazoline, etc., have been synthesised.