A simple, sensitive, selective, precise and stability indicating high-performance thin-layer chromatographic method was developed for the determination of tamsulosin (TAM) in bulk and tablet formulation. Validation was carried out in compliance with International Conference on Harmonization guidelines. The method employed thin-layer chromatography aluminium plates pre-coated with silica gel 60F254 as the stationary phase and the mobile phase consisted of acetonitrile/methanol/dichloromethane (2.0: 1.0: 2.0, v/v/v). This solvent system was found to give compact spots for tamsulosin (R f = 0.27 ± 0.02). Densitometric analysis of TAM was carried out in the absorbance mode at 286 nm. Linear regression analysis showed good linearity (r 2 = 0.9993) with respect to peak area in the concentration range of 300-800 ng per band. The method was validated for precision, accuracy, ruggedness and recovery. Limits of detection and quantitation were 8.49 and 25.72 ng per band, respectively. TAM was subjected to acid and alkali hydrolysis, oxidation, photo degradation, dry heat and wet heat treatment. The drug underwent degradation under acidic, basic and photolytic conditions. The degraded products were well separated from the pure drug. Statistical analysis proved that the developed method, used for quantification of TAM as a bulk drug and present in pharmaceutical tablets, was reproducible and selective. {\textcopyright} 2009 Vieweg+Teubner | GWV Fachverlage GmbH.