Objective To evaluate the impact of age on the bladder-urethral function and the outcome of transurethral resection of the prostate (TURP) in the elderly men with benign prostatic hyperpiasia (BPH). Methods The elderly men with BPH undergoing TURP were divided into young elderly group [n=158, mean age of 68 + 4 years] and elderly group [n=47, mean age of 80± 3 years]. All patients were evaluated by International Prostate Symptom Score (IPSS). Quality of life (QOL). transrectal ultrasound and urodynamic examination one week before TURP, and they were followed by IPSS, QOL. free uroflowmetry and postvoid residual urine volume (PVR) measurement at 3 months after TURP. Results The incidence rates of detrusor overactivity, low compliance bladder, detrusor underactivity and benign prostatic obstruction in elderly group were 70%, 34%, 19% and 77% respectively, and they were significantly higher than in young elderly group (42%, 18%, 6.3% and 58%,x2 =10.623, 4.328, 5.637,4.771,P<0.05). However, the mean max detrusor voided pressure [62±29) cm H2O] was significantly lower in elderly group than in young elderly group [(76±22) cm H2O,t =3.265, P<0.05]. Moreover, the mean prostatic length, static functional length and bladder neck pressure were (52±8) mm, (63±11) mm and (36 15) cm H2O respectively, they were significantly higher in elderly group than in young elderly group [(47±7)mm, (59±6) mm and (25±13) cm H2O, t=4.157, 3.388 and 4.912,P<0.05]. The IPSS, QOL and PVR were significantly lower after TURP than beforeTURP, and the max flow rate (MFR) was significantly higher after TURP than before TURP in both groups (tyoung elderly group= 19.744, 64.671, 23.342 and 27.504;t elderly group= 27.308, 19.311,9.694 and 11.671, P<0.05). However, the MFR was significantly lower in elderly group than in young elderly group, and PVR and QOL were significantly higher in elderly group than in young elderly group after TURP (t=3.493, 15.245 and 10.750, P<0.05). Conclusions The risk of bladder-urethral dysfunction is increased and the therapeutic effects of TURP is decreased with ageing in the elderly men with BPH. It would be beneficial to have an urodynamic study for their treatment.