Serial passage through disinfectants at sub-minimal inhibitory concentrations induced antibiotic resistances in 30.5% of the derived phenotypic variants of five strains of Staphylococcus aureus. A proportion of these phenotypic variants showed changes in their phage typing pattern by becoming susceptible to an increased number of phages, and a change from phage non-typable to typable was also observed. A loss of temperate phages was noted in some variants when subjected to reverse phage typing.