Asymptomatic bacteriuria is a quite common finding, and most of the times benign. A 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 bacteriuria has been shown to improve patient outcomes. Screening and treatment of asymptomatic bacteriuria is only recommended for pregnant women or for patients prior to selected invasive genitourinary procedures. Healthy women identified with such finding on population screening subsequently experience more frequent episodes of symptomatic infection, but antimicrobial treatment of asymptomatic bacteriuria does not decrease the occurrence of these episodes. 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. If there is a symptomatic bacteriuria we must talk about a urinary tract infection, most of the times uncomplicated and occurring in women who are sexually active, nevertheless, it is important to know if you are treating an acute nonobstructive pyelonephritis, a complicated urinary tract infection, a relapse or a reinfection in order to warrant the appropriate treatment.