Asymptomatic bacteriuria (ABU) is a common condition. Although it is harmless in most clinical situations, clinicians often treat patients with ABU despite clinical evidence. Unnecessarily treatment leads to antibiotic-associated morbidities and selection of antimicrobial resistance. The diagnosis of ABU is based on urine cultures, with significant bacterial growth of the same species in two consecutive samples. Evidence shows that in most clinical situations treatment of ABU is not beneficial to the patients. Therefore, screening and treatment of ABU is not recommended in patients without relevant risk factors, patients with diabetes mellitus, postmenopausal women, elderly institutionalized patients, patients living with renal transplants, patients prior to joint replacement, patients with indwelling catheters, and patients with recurrent urinary tract infections (UTI). Treatment of ABU is harmful in patients with recurrent UTI leading to an increased number of recurrences and the selection of antibiotic-resistant uropathogens. In pregnant women untreated ABU is associated with an increased risk of symptomatic UTI, low birthweight, and preterm delivery, although the results of a recent trial have challenged these previous findings. In patients undergoing urological procedures breaching the mucosa untreated ABU resulted in a higher risk of postoperative UTI and sepsis. Therefore, screening and treatment of asymptomatic bacteriuria is recommended in pregnant women and prior to urological procedures breaching the mucosa.