A selective, specific and sensitive stability-indicating high-performance liquid chromatographic method was developed and validated for the determination of Tamsulosin in in pharmaceutical dosage forms. Celecoxib was used as Internal Standard (IS). The chromatographic conditions comprised of a reversed-phase Lichrocart / Lichrosphere C18 column (250 x 4.0 mm packed with 5 μ) with mobile phase consisting of a mixture of Acetonitrile: T.D.W. in the ratio (40: 60). Flow rate was 0.8 mL / min. Detection was carried out at 275 nm. The retention time of Tamsulosin HCl and Celecoxib were found to be 1.608 and 2.767min respectively and the linear regression analysis data for the calibration plots showed good linear relationship in the concentration range 1 - 200 μg/mL. The value of correlation coefficient, slope and intercept were, 0.9995, 0.7453 and 0.4584, respectively. Tamsulosin HCl was subjected to stress conditions of degradation in aqueous solutions including acidic, alkaline, oxidation, photolysis and thermal degradation. The developed method was validated with regard to linearity, accuracy, precision, selectivity and robustness and the method was found to be precise, accurate, linear and specific. The method was employed successfully for identification and determination of Tamsulosin in pharmaceutical preparations.