A common dilemma in clinical medicine is whether to treat asymptomatic patients who present with bacteria in their urine. There are few scenarios in which antibiotic treatment of asymptomatic bacteruria has been shown to improve patient outcomes. Because of increasing antimicrobial resistance, it is important not to treat patients with asymptomatic bacteriuria unless there is evidence of potential benefit. Women who are pregnant should be screened for asymptomatic bacteriuria in the first trimester and treated, if positive. Treating asymptomatic bacteriuria in patients with diabetes, older persons, patients with or without indwelling catheters, or patients with spinal cord injuries has not been found to improve outcomes.