Proliferation of different brands of antibiotics including ampiclox (a notable penicillinase inactivator) was considered a relevant factor in the antibiotic resistance of Staphylococcus aureus. Consequently the antibiogram and susceptibility of 20 clinical strains and a control strain (NCTC 6571) of Staphylococcus aureus to 10 different brands of ampiclox were determined by disk diffusion and tube broth dilution methods. The control strain was found sensitive to ampicilin, augmentin R and cloxacillin in the antibiogram, and to all the l0 brands of ampiclox, with the MIC's of either 0.125 or 0.25µg/mI among the clinical strains. This result, compared with the MIC's obtained in the range of 0.125µg/ml to > 60µg/mI, varying among the brands of ampiclox against the 20 clinical strains, indicates contrasting inhibitory activity among the different brands but reflective of the worrisome level of resistance to antibiotics by Staph. aureus. However, this resistance to most of the brands of ampic1ox could not be associated with brand variation having found the control strain sensitive to all the brands of ampiclox.