Nowadays, ureteroscopy is highly effective and minimally invasive therapeutic and diagnostic method which is not connected with the risk of complications and with correlation of intracorporal lithotripsy and it is optimal at ureterolithiasis. The aim of the research is to analyze the causes and the character of late postoperative complications which occur in patients with ureterolithiasis after ureterorenoscopy and contact lithotripsy using ultrasound lithitriptor. After ureterorenoscopy with contact lithotripsy or lithoextraction from 1372 patients in 96 (6,9%) cases further postoperative complications were detected: in 81 (84,4%) vesicoureteral reflux was detected, and in 15 (15,6%) - ureteric stricture. It was proved by us that when localization of the stones in the upper and the middle thirds, the probability of the development of late postoperative complications does not depend on the size of the stones, with the localization of the stones in the lower sections of the ureter, complications are found much more often with stones sizes of 1,0 cm and more. Analyzing the density characteristics of stones, it should be noted that, regardless of the location of the stone, the possibility of the development of late postoperative complications increases with a stones density of 1000 HU and more.