Asymptomatic bacteriuria, defined as the presence of bacteria in the urine in the absence of urinary symptoms, is a common clinical finding that often warrants a decision about whether to initiate antimicrobial therapy. There are few indications to treat asymptomatic bacteriuria, and inappropriate treatment contributes to the development of antimicrobial resistance. In 2019, the Infectious Diseases Society of America revised its 2005 guidelines on asymptomatic bacteriuria, incorporating new evidence. The updated guidelines recommend screening and appropriate treatment for asymptomatic bacteriuria in pregnant women and in individuals undergoing endourological procedures associated with mucosal trauma. The guidelines recommend against screening and treatment in infants and children; healthy adults, including nonpregnant pre- and postmenopausal women; and patients with diabetes mellitus, long-term indwelling catheters, or spinal cord injuries. The guidelines also recommend against screening and treatment in patients undergoing nonurological surgery, patients who have had a kidney transplant more than one month prior, recipients of other solid organ transplants, or those with impaired voiding following spinal cord injury. Although delirium in older adults can be caused by a urinary tract infection, the guidelines recommend that patients with delirium and no urinary or systemic symptoms be assessed for other causes of delirium, rather than initiating treatment for asymptomatic bacteriuria, because treatment has not been shown to have any beneficial effect on clinical outcomes.