ABSTRACTAn efficient and simple RP-HPLC method has been developed and validated for simultaneous determination of Repaglinide (REPA) and Metformin Hydrochloride (MET). The separation was carried out using mobile phase consisting of Phosphate buffer: Methanol (30:70). The column was used Luna 5u C18 (2) 100A of size 0.25m *4.6mm with flow rate of 1.0 mL/min. Drug peaks were well separated and were detected by a UV detector at 260 nm.. The described method was linear over concentration range of 10-50 ppm for assay of REPA and MET. The retention time of REPA and MET was found to be 4.31. The method has been validated according to ICH guidelines with respect to system suitability, specificity, precision, accuracy, ruggedness and robustness. Metformin limit of detection (LOD) and limit of quantification (LOQ) were 0.0386 mg/ml and 0.1169mg/ml respectively while LOD and LOQ for Repaglinide were 0.0339?g/ml and 0.1025?g/ml respectively and thus can be successfully applied for the routine analysis of REPA and MET in bulk and marketed dosage forms. Keywords: Repaglinide, Metformin Hydrochloride, RP-HPLC, Simultaneous estimation, Validation