The International Conference on Harmonization (ICH) guideline entitled "Stability testing of new drug substances and products" requires that stress testing be carried out to elucidate the inherent stability characteristics of the active substance. Acidic, alkaline, oxidative and photolytic stability are required. An ideal stability indicating method is one that quantifies the standard drug alone and also resolves its degradation products. Therefore, it was thought to develop the stability indicating HPLC method for the drug candidate lamivudine by using modern statistical application i.e first order factorial design (Plackett -Burmann design). In addition stress degradation study will be carry out to assess the effect of various stress conditions like acid, alkali, oxidation, UV light, heat etc. on stability of drug.