Objective To investigate the diagnosis and surgical management of ureteral obstruction after renal transplantation.Method A respective study was performed on 15 cases of ureteral obstruction who received renal allografts.All of the cases were confirmed,including 5 cases of stenosis of ureterovesical junction,4 cases of stenosis of distal ureter,2 cases of blood clot blockage,2 cases of edema due to perforation of distal ureter,1 case of ureteral calculi,and 1 case of extrinsic compression of hematoma.All 14 patients underwent open surgical management to reestablish ureter with D-J catheter as stent for 12-16 weeks.One patient was subjected to percutaneous nephrostomy followed by percutaneous ureteroscopy,the obstructed site was identified at ureterovesical junction and antegrade balloon dilation and D-J stent in ureter were performed subsequently.Result Fifteen patients were diagnosed as ureteral obstruction by colour Doppler ultrasound and MRU.All of the patients were resolved the obstructions after surgical managements and the renal function got improved.No reobstruction occured during one year follow-up period.Conclusion Colour Doppler ultrasound and MRU can definitely be used to diagnose ureteral obstruction after renal transplantation.Early diagnosis and surgical management are very important.Open surgical management of the obstructed ureter is an effective method.Antigrade balloon dilation is a therapeutic approach to treat ureteral obstruction.