When a urinary catheter is not inserted using proper technique, becomes unclean, or remains in place for too long, microorganisms can travel through the catheter lumen or along the outside of the catheter and infect the bladder or kidneys, resulting in a catheter-associated urinary tract infection (CAUTI). Urinary tract infections resulting from catheter use are one of the most common health care–associated infections. The insertion of a urinary catheter is considered to be routine care. Improving practices of placement and removal of urinary catheters requires education aimed at changing the habits of nurses and physicians. Clinicians should follow evidence-based guidelines, including using aseptic technique for site preparation and supplies and limiting use and duration of the placement of urinary catheters. Perioperative personnel need to be aware of the risks of catheterization and take steps to prevent CAUTIs. This article discusses CAUTIs, including causes and strategies for prevention.