Introduction. Urinary drainage is a key part of ureteropelvic junction obstruction treatment. Both external and internal drainage methods have been widely used for many years, but there is now relevant research comparing these methods and their impact on surgical outcomes in adults. The aim of the current research was to assess the efficacy and safety of two different types of urinary drainage on adult pyeloplasty. Material and methods. We conducted a retrospective and prospective clinical controlled study in the Department of Urology at the Republican Clinical Hospital from Chisinau. We reviewed 118 consecutive adult pyeloplasties for ureteropelvic junction obstruction. In 62 (52.54%) patients, we used double-J ureteral stent insertion (DJ); in another 56 (47.46%) patients, we used different types of external drainage (ED): uretero-pyelo-nephrostomy, nephrostomy, or a combination of both. Operative time, hospital stay, use of analgesics, overall complications, type of complications, and success rates were compared between the two groups. Results. The mean operative time in the DJ group was 93.52±18.10 min. vs. 95.77±20.48 min. in the ED group (p = 0.001). The average postoperative hospital stay in the DJ group was 8.45±2.02 days vs. 14.71±3.45 days in the ED group (p=0.000). The DJ group used 7.77±3.48 analgesics on average, while the ED group used 9.86±4.64 (p = 0.006). Overall complication rate was 9.68% in the DJ group and 32.14% in the ED group (p = 0.002). The most frequent complication for all patients was acute pyelonephritis (12.71%): 4.84% in the DJ group vs. 21.43% in the ED group (p = 0.007). The success rate was 96.77% in the DJ group and 92.86% in the ED group. Conclusions. Both urinary drainage methods appear equivalent concerning overall success rates, but double-J ureteral stents are associated with a shorter operating time, fewer postoperative pain medications, a shorter postoperative hospital stay, and a lower number of postoperative complications compared with external urinary drainage methods.