A new gradient reverse phase high performance liquid:chromatography (RP-HPLC) method was developed and validated for simultaneous estimation of tenofovir disoproxil fumarate, cobicistat, emtricitabine and elvitegravir. The chromatography was achieved On Hypersil BDS, C18 column, (100 x 4.6 mm, 5 m) with a mobile phase composed of phosphate buffer (pH 3) and acetonitrile taken in gradient mode at a flow rate of 0.8 Detection was performed at 245 urn by using PDA detector. The retention times for tenofovir disoproxil fumarate, cobicistat, emtricitabine and elvitegravir were 2.1, 4.3, 5.2 and 8.5 min, respectively. This method was validated for parameters like system suitability, linearity, precision, specificity, accuracy and robustness. This method was successfully applied for the estimation of tenofovir disoproxil fumarate, cobicistat, emtricitabine and elvitegravir in bulk drug and tablet dosage form.