Analytical method was developed using HPLC Shimadzu (with power stream) gradient chromatographic technique. Data were passed through the spinchrom software. Separation was achieved on hypersil based deactivated silica C18 (250 mm × 4.6 mm, 5 μm) column using mobile phase composition of 0.05 M Potassium phosphate buffer: Methanol (60 v/v:40 v/v), (15 v/v:85 v/v), (60 v/v:40 v/v), adjusted to pH 4 with 1% orthophosphoric acid. Makeup volume with water. The flow rate of mobile phase was maintained at 1 ml/min with wavelength 225 nm UV detection. The Retention Time (RT) found for Atazanavir sulphate (ATZ), impurity A and impurity 5 was at 5.3 min, 6.23 min and 14.53 min respectively with an injection volume of 20 ml and the detection was made at 225 nm. Validation of the method was successfully established by performing various validation parameters such as accuracy, precision, specificity, linearity, Limit of Detection (LOD), Limit of Quantification (LOQ), ruggedness, robustness, according to ICH guidelines.