A systematic study for the determination of sulphamerazine, sulphadiazine and sulphat- hiazole applying atomic absorption spectrophotometry is undertaken.(The method is based on the precipitation of sulphamerazine by Cu (II), sulphadiazine by sulphadiazine by Cd (II) and sulp- hathiazole by Co (II) under optimum conditions followed by the determination of the unreacted metal ion as well as that in the precipitate. The conditions for a quantitative stoichiometric precipitation of the sulphonamides are discussed.