A simple, economic, accurate Absorption ratio method was developed for the simultaneous estimation of Atazanavir Sulphate and Ritonavir in bulk and tablet dosage form. 0.1M Hydrochloric acid was used as a diluent. 1% Sodium Lauryl Sulphate is used as surfactant to enhance solubility of drugs in 0.1M hydrochloric acid. The absorptions were observed at 262.8nm and 297nm which were selected based on overlap spectra of Atazanavir Sulphate and Ritonavir. The linearity range was found to be 10-20 mg/ml. The proposed method was validated. The reports was expressed that the proposed method was found to be simple, precise, accurate and rapid for the simultaneous estimation of Atazanavir Sulphate and Ritonavir in bulk and tablet dosage form using absorption ratio method.