A novel, sensitive and selective reverse phase high performance liquid chromatographic method was developed for quantitative determination of nevirapine in its extended tablet dosage forms. The synthetic non-nucleoside reverse transcriptase inhibitor analogues (NNRTI) nevirapine form one of the extended dosage in HIV. It belongs to a group of anti-HIV medicines called non-nucleoside reverse transcriptase inhibitors (NNRTIs). The method is applicable to the quantification of related compounds of Nevirapine form one of the fixed extended dosage. Chromatographic separation of nevirapine from the possible impurities and the degradation products was achieved on a Supelcosil LC-ABZ, 150 x 4.6 mm, and 5.0 μm column. Ammonium orthophosphate pH 5.0 as mobile phase A and acetonitrile taken as mobile phase B in the ratio (85 : 15). The flow rate was 1.0 mL/min, and the detection was done at 220 nm. The above developed HPLC method was further subjected to hydrolytic, oxidative, photolytic and thermal stress conditions. The performance of the method was validated according to the present ICH guidelines for specificity, limit of detection, limit of quantification, linearity, accuracy, precision, and ruggedness.