Background: Cystectomy with urinary diversion (CUD) is a highly morbid surgery. Despite implementing an enhanced recovery after surgery (ERAS (R)) protocol, postoperative respiratory complications (PRC) within 30 days after surgery remain frequent. This study aims to identify patients at higher risk of developing PRC after CUD. Methods: We conducted a retrospective analysis of 242 patients who underwent CUD at Lausanne University Hospital from 2012 to 2022, adhering to ERAS (R) guidelines. Data on postoperative complications, including pneumonia, respiratory failure, pulmonary embolism, lobar atelectasis, and pleural effusion, were analyzed. Chi-square and Mann-Whitney U tests compared patients with and without PRC. A multivariable Cox model identified independent prognostic factors. Results: PRC occurred in 41 patients (17%). Those with PRC experienced longer hospital stays and higher 30-day mortality rates. Poor ERAS (R) compliance was a significant risk factor. Multivariable analysis showed pneumonia was associated with postoperative ileus, while pulmonary embolism correlated with infectious and cardiovascular complications. Conclusions: PRC result in extended hospitalization and decreased survival. Rigorous adherence to ERAS (R) protocols, including early mobilization, respiratory physiotherapy, and avoiding nasogastric tubes, is essential for preventing PRC.