A new method was established for simultaneous estimation of elvitegravir, tenofovir, emtricitabine and cobicistat by using Reverse Phase-High Performance Liquid Chromatography (RP-HPLC) method. Chromatographic separations were carried using Inertsil ODS (4.6 × 250 mm, 5 μm) column with a mobile phase composition of 0.1% ortho phosphoric acid buffer and Acetonitrile (30:70) have been delivered at a flow rate of 1 ml/min and the detection was carried out using waters HPLC auto sampler, separation module 2695 with Photo Diode Array (PDA) detector 2996 at wavelength 252 nm. The retention time for elvitegravir, tenofovir, emtricitabine and cobicistat were 2.287, 2.957, 5.652 and 9.801 min respectively. The correlation coefficient values in linearity were found to be 0.999 and concentration range 75-225 μg/ml for elvitegravir, 150- 450 μg/ml for tenofovir, 100-300 μg/ml for emtricitabine and 75-225 μg/ml for cobicistat respectively. The accuracy recovery was found to be 100.11%, 100.26, 100.64 and 100.08% for elvitegravir, tenofovir, emtricitabine and cobicistat respectively. The Limit of Detection (LOD) and Limit of Quantification (LOQ) for Elvitegravir was found to be 2.98 and 9.98, LOD and LOQ for Tenofovir was found to be 3.02 and 10.02, LOD and LOQ for Emtricitabine was found to be 3.00 and 10.00 and LOD and LOQ for Cobicistat was found to be 3.00 and 10.02. The force degradation studies were performed for the dosage form and the results are within the limits. The results of study showed that the proposed RP-HPLC method is a simple, accurate, precise, rugged, robust, fast and reproducible, which may be useful for the routine estimation of elvitegravir, tenofovir, emtricitabine and cobicistat in pharmaceutical dosage form.