An accurate, precise and reproducible RP-HPLC method for the simultaneous determination of Lamivudine and Raltegravir in the bulk API dosage form has been developed and validated. Chromatographic separation was carried out on Agilent C18 (100×4.6mm, 3.5u particle size) column using mobile phase composed of phosphate buffer (PH3.0): acetonitrile (ACN) in ratio 60:40 at a flow rate of 0.8ml/min. The analyte was monitored using DAD detector at 231nm. The retention times were found to be 1.12 and 4.08 for Lamivudine and Raltegravir respectively. The linearity for each were found in the range 10-60µg/ml and their regression values are 0.998 and 0.999 respectively. The developed method was validated as per ICH guidelines.