Double J stent is an essential tool in urology, being a basic part of many urological procedures. However, some issues related to their use still occur. Our study aimed to evaluate an important number of procedures, the complications of ureteral stents, and their prevention and treatment retrospectively. We evaluate 50,000 procedures performed between 1996 and 2021 on 36,688 patients. According to the stenting duration, the cases were divided into short-term (less than 6 weeks – 34,213 procedures), respectively long-term stenting (more than 6 weeks – 15,757 procedures). The indications of stenting for both groups were noted. The total number of complications was 41,369. We encountered 153 cases (0.3%) of JJ stent malposition, of which 3 cases were into the retroperitoneum, one case with parenchymal perforation and hematoma. Considering the double J migrations, we found proximal migration in 427 cases (0.9%) and distal double J migrations in 352 (0.7%) cases. The obstruction of the ureteral stent, causing inefficient drainage, was encountered in 925 cases, while irritative bladder symptoms occurred in 16,326 cases (32.7%). Hematuria was observed in 5,213 cases, in 7 cases blood transfusion being necessary. Urinary tract infection was diagnosed in 7,436 cases (14.8%). Stent encrustation and calcification occurred in 832 cases, while stent fragmentation was noted in 52 cases. Double J stent complications should be promptly evaluated and treated. Encrustation and stone formation in forgotten stents often lead to serious complications and should be managed with stent removal and combined endourological techniques.