To evaluate the efficacy of tamsulosin on BPH patients with an acute urine retention on a trial without catheter (TWOC). This study was a post test only-placebo group design comparing residual urine in BPH patients with an acute urine retention on TWOC between groups treated with tamsulosin and placebo. The efficacy with transulosin or placebo on the 3nd and 14th day was analyzed using the Chi …