This study was designed to investigate the LUTS after endocrine therapy and their effects on the quality of life in elderly patients with PC. The elderly patients with PC who had no progression after receiving endocrine therapy and had data of total prostate volume (TPV) before receiving endocrine therapy were asked to complete the questionnaire of International Prostate Symptom Score (IPSS) questionnaire with quality-of-life (QOL) assessment. Transrectal ultrasound assessment was performed in all patients to measure prospectively the TPV, maximum flow rate (Qmax) and residual urine volume (RUV) after endocrine therapy. A total of 42 patients aged 76–98 (87.8±5.6) years finished the investigation, with duration of endocrine therapy ranged 1–17 (6.5±4.2) years, including orchidectomy in 18 patients, medical castration with luteinizing hormone-releasing hormone analog in 24 patients. The TPV [28–53 (34.9±14.7)ml] after endocrine therapy was significantly decreased compared to that before endocrine therapy [28–53 (34.9±14.7)ml]. The Qmax was 8.7±3.8ml/s, RUV measured by B-Ultrasound was 37.5±14.9ml. However, all patients presented LUTS with various severities, and had an IPSS score of 23.7±4 that was consisted by a score of 15.5±2.8 for storage symptoms, 8.2±2.2 for voiding symptoms, and had QOL score of 4.2±1.8. The Spearman rank correlation test showed a positive correlation between IPSS score, score of storage symptoms and QOL (r1=0.83, P<0.01 and r2=0.81, P<0.01); but no such correlation was detected between score of voiding symptoms and QOL (r3=0.43, P=0.49). The more important is that the storage symptoms contribute significantly more effects on QOL than the voiding symptoms (P=0.0032). Based on these results, it was proposed in our study that aging bladder associated with the storage symptoms might be the key reason for the LUTS sustained during the endocrine therapy in elderly patients with PC, especially in LUTS patients who mainly present as storage symptoms and could not be controlled by repeated treatments.