Background Bladder recurrent disease is still a challenge in the treatment of upper tract urothelial carcinoma (UTUC).This controlled study aims to investigate the efficacy of early clipping of the distal ureter prior to nephroureterectomy (NU)to prevent bladder recurrence after UTUC.Methods Patients with clinical diagnosis of UTUC were subjected to open trans-peritoneal NU and were randomly divided into two groups.One group received modified NU:clipping the distal ureter prior to NU; while the other group underwent traditional standard NU.Subsequent bladder recurrence was the primary endpoint.Results From January 2007 to December 2009,85 eligible cases were enrolled in this study.Modified NU and standard NU were performed on 42 and 43 patients,respectively.Operation time ((215.73±21.26) minutes vs.(220.19±15.35)minutes),blood loss ((105.15±11.32) ml vs.(110.12±9.07) ml),transfusion event (11.20％ vs.9.78％),and the in-patient time (10.0 days vs 9.5 days) were not significant between the two groups.After a median follow-up of 28 months (5-60),six (14.3％) cases who received modified NU had bladder recurrence,which was significantly lower compared with 15 (34.9％) patients from the group that underwent standard NU (P=0.026).In univariate and multivariate analysis,tumor grade (HR 4.33,95％CI 2.66-6.30,P=0.01) and operation type (HR 2.35,95％CI 1.53-3.48,P=0.041) were independent risk factors for subsequent bladder recurrence after UTUC.Conclusions Clipping the distal ureter at the beginning of NU significantly reduces bladder recurrence after UTUC.It is reasonable to conclude that clipping the distal portion of ureter trans-peritoneal is an effective surgical procedure for the treatment of UTUC.