We investigated lower urinary tract symptoms (LUTS) and the urinary flow rates of patients who underwent transurethral resection of the prostate (TUR-P) for benign prostatic hyperplasia to determine the persistence of the efficacy of TUR-P. We mailed questionnaires for evaluation of LUTS to 1236 patients who had received TUR-P. In addition, we encouraged them to visit a clinic for uroflowmetry if possible. LUTS using the International Prostate Symptom Score (IPSS) and QOL index, and uroflowmetry were analyzed in 847 (68.5%) and 150 patients (12.1%), respectively. The IPSS of patients who had received TUR-P more than 5 years earlier was higher than that of patients who had received it in the preceding 5 years. However, more than 80% of the patients in both groups were satisfied with their urinary condition at evaluation. Although no obvious change in the maximum urinary flow rate was observed in the patients who had received TUR-P in the preceding 5 years, it was significantly decreased in the patients who had received it more than 5 years earlier. The tendency was marked in the patients when TUR-P was performed at 70 years of age and older. Although the change in detrusor function determined by the age at surgery and the postoperative period may cause LUTS and reduce the urinary flow rate in the long-term after TUR-P, the efficacy of TUR-P appears to last for long periods in terms of the maintenance of QOL.