We compared the efficacy of naftopidil with that of tamsulosin hydrochloride for benign prostatic hyperplasia patients. Eighty-five patients without improvement of quality of life (QOL) score by the administration of 50-75 mg naftopidil for more than four weeks were assigned to receive doses of 0.1-0.2 mg tamsulosin hydrochloride and 89 patients without improvement of QOL score by the administration of 0.1-0.2 mg tamsulosin hydrochloride for more than four weeks were assigned to receive doses of 50-75 mg naftopidil once a day for 8 weeks. International prostate symptom score, maximum flow rate, residual urine volume and side effect profile were determined before the administration of the first medicine, before the administration of the second medicine and after 8 weeks of treatment with the second medicine. In the group without improvement of QOL score by naftopidil, significant improvements in symptoms of urgency, weak stream and straining were observed after 8 weeks of treatment with tamsulosin hydrochloride. In the group without improvement of QOL score by tamsulosin hydrochloride, significant improvements in symptoms of incomplete emptying, intermittency and nocturia were observed after 8 weeks of treatment with naftopidil. In conclusion, improvement of symptoms by each alpha 1-blocker differs symptom by symptom. Tamsulosin hydrochloride was superior to naftopidil for the symptoms of urine flow and naftopidil was superior to tamsulosin hydrochloride for the symptom of nocturia.