A specific, accurate, precise and sensitive stability indicating RP HPLC method was developed and validated for the simultaneous determination of atorvastatin (ATR), metformin (MET) and glimepiride (GLM) in bulk drug and pharmaceutical dosage form in the presence of its degradation products. An isocratic RP HPLC method was developed with a Hibar C18 (250 X 4.6 mm i.d., 5μ) column and Acetonitrile: 10 mM Ammonium acetate (pH 3.0, adjusted with acetic acid) in the ratio of 40:60 % v/v as mobile phase. The flow rate was maintained at 1 mL/min and detection was carried out using UV detector (245 nm). The drugs were subjected to stress conditions of degradation in aqueous solutions including hydrolysis, oxidation and photolysis. Degradation was carried out for 24 hrs at room temperature. The developed method provided better separation of the drugs from the degradation products. The linearity of the proposed method was carried out in the range of 0.5 – 12 μg/mL, 25 – 250 μg/mL and 0.2 – 1.2 μg/mL for ATR, MET and GLM respectively. The limits of detection and quantification were found to be 10 ng/mL, 1 ng/mL, 1ng/mL and 30 ng/mL, 4 ng/mL, 5 ng/mL for ATR, MET and GLM respectively.