1.0 Abstract: A sensitive and precise stability indicating RP-HPLC method was developed and validated for the simultaneous determination of known related substances, isomer-I(RRT 0.85), isomer-II(RRT 1.13) and other unknown related substances of nebivolol in nebivolol tablets. The chromatographic separation was performed on Hypersil BDS Phenyl (250mm x 4.6mm) 5μm, using isocratic elution of buffer and acetonitrile (80:20 v/v) at flow rate of 1.2mL/min. UV detection was performed at 220 nm. Total run time was 70 min within which main compound and 2 other known and major unknown impurities were separated. The method was validated for accuracy from LOQ to 150 % of actual standard concentration. The system & intermediate precision was observed by analyzing the samples with two different analysts, systems, days & columns. Linearity was established at LOQ 0.036μg/mL and lowest successful determination observed at 0.012μg/mL for nebivolol and their known and unknown impurities. Stability of stock & sample aliquot was observed for 48 hrs and found satisfactory at room temperature. The method was successfully applied for the determination of nebivolol related substances in a pharmaceutical formulation of without any interference from common excipients and diluent. All the validation parameters were within the acceptance range, and concordant to ICH guidelines.