An accurate, precise and reproducible Reverse Phase High Performance Liquid Chromatographic (RP-HPLC) method was developed and validated for the estimation of Metformin Hydrochloride, Glimepiride and Atorvastatin in Pharmaceutical dosage forms. In this method Qualisil gold C18 column (250mmx4.6mm I.D., 5µm particle size) with mobile phase containing 0.1% TFA in Water (pH adjusted to 2.92 with ammonia) and Methanol in the ratio of 28: 72v/v was used. The flow rate was 1ml/min. and the detection wavelength was 235nm1-2. The linearity was observed in the range of 50 - 225µg/ml, 0.2 - 0.9µg/ml and 1 – 4.5 µg/ml for Metformin Hydrochloride, Glimepiride and Atorvastatin with correlation coefficient of 0.9992, 0.9992, and 0.9997 respectively. Retention times were 3.1min, 7.8min, and 10.1min for Metformin Hydrochloride, Atorvastatin and Glimepiride respectively. The proposed method was validated for Linearity, accuracy, precision and Robustness. The proposed method was validated as per ICH guidelines and can be applied for routine quality control analysis of pharmaceutical dosage forms used for Multidrug therapy containing Metformin Hydrochloride, Glimepiride and Atorvastatin. Key words: RP-HPLC, OPA, Multidrug therapy, ICH, Validation.