This review highlights recent findings regarding complicated urinary tract infections (UTIs). We review recently published randomized controlled trials, Cochrane reviews, and meta-analyses. Topics covered include new findings on the genetics of acute pyelonephritis, methods to prevent catheter-associated UTI, duration of treatment for catheter-associated UTI, and reimbursement changes for Medicare patients who develop nosocomial UTI in US hospitals. Future studies on complicated UTI are needed to better define this complex disease and its management and to confirm the clinical significance of different prevention strategies.