Objective To report the experiences on the diagnosis and treatment of duplication of kidney ureter and bladder. Methods Nine cases of duplication of kidney ureter and bladder from 1996 to 2008 were reviewed.Six cases of duplicated kidney ureter occurred in the left side and 2 cases in the right side,1 case bilateral kidney ureteral duplication.Of 8 cases with unilateral duplicated,duplicated bladders were incompleteness.And the patient with bilateral duplicated,whose duplicated bladder was completeness,was diagnosed with duplication of urethra,uterine,bilateral ovary and oviduet tubes,and also suffered from duplicated uterine prolapse Ⅱ,vaginal anterior wall bulging and duplicated vesicocele.There were two cases whose duplicated kidney losed function because of severe hydronephrosis,and 7 cases existed kidney secretion function. Excision of duplicated kidney ureter and bladder were performed on 2 cases with non-functional duplicated kidney.6 cases had undergone duplicated bladder excision and duplicated ureteral bladder replantation.The special case had undergone duplicated urinary bladder urethra uterine and bilateral annexes excision,and duplicated ureteral bladder replantation. Results The operation was successful in all paients without leakage and ureter stump syndrome.Three months after operation,ureter bladder imaging showed no ureteral reflux in 7 cases of ureteral bladder replantation.IVU were reviewed 12 months after operation:2 cases undergoing duplicated kidney excision showed that the function of residual kidney were normal,7 cases of replantation that the shape and function of sick side kidney and duplicated kidney were good. The patient who suffered from duplicated uterine simultaneously got pregnancy 1.5 years after operation. Conclsions Image examinations may help to diagnose the duplication of kidney ureter and bladder. The main treatment is surgery. Understanding the function of duplicated kidney and the shape of kidney ureter and bladder should be considered before operation. The goal of surgery should be relieving pain,protecting the function of duplicated kidney and minimizing the risk of infection.