The alpha(1)-adrenoceptor antagonist, tamsulosin, is selective for alpha(1A)- and alpha(1D)- over alpha(1B)-adrenoceptors. Both placebo-controlled and comparative studies with other agents have demonstrated tamsulosin to be an effective treatment for patients with lower urinary symptoms suggestive of benign prostatic hyperplasia. Its effectiveness appears to be maintained over many years. Tamsulosin may also effectively reduce lower urinary tract symptoms in other urological diseases. A dose of tamsulosin 0.4 mg/day has a tolerability close to that of placebo and has little, if any, blood pressure lowering effects. Tolerability and lack of blood pressure lowering are maintained even in high-risk patients such as those with cardiovascular comorbidity and/or comedication. Apart from adrenoceptor subtype-selectivity, a smooth pharmacokinetic profile of its modified-release formulation and a selective accumulation in target tissues may contribute to an excellent efficacy:tolerability ratio.