A series of sulphanilamides derived from N-carbo and heterocyclic hydroxamides have been synthesised, since a number of N⁴-acyl sulphanilhydroxamides have been favourably reported on in preliminary experimental bacterial infections. Among the latter wassulphabenamide or N⁴-caproyl sulphanylhydroxamide, which was said to be effective clinically in streptococcal infections and tuberculosis. This is a new class of sulphanilamides involving the preliminary synthesis of some hitherto unknown substituted aryl- and heterocyclic hydroxamides. The compounds of this series so far prepared are the N⁴-n-butyryl-, the N⁴-n-valeryl-, and the N⁴-n-caproylsulphanilyl derivatives of β-3-chlorophenyl-, β-4-chlorophenyl-, β-2∶5-dichlorophenyl-, and β-3∶4-dichlorophenyl-hydroxylamines.