Acute uncomplicated cystitis and acute uncomplicated pyelonephritis are two frequently encountered urinary tract infections (UTI) in premenopausal, healthy females. Recent epidemiological investigations showed that the incidence of these infections is higher than expected. Surveys on healthcare practices in North America revealed a high variability in the therapy of uncomplicated UTI. Standardized criteria for diagnosis and therapy of uncomplicated UTIs therefore are important in order to achieve sufficient sensitivity and specificity in clinical practice. The Infectious Diseases Society of America (IDSA) developed evidence-based guidelines for the treatment of acute uncomplicated cystitis and acute uncomplicated pyelonephritis, which were recently updated by other expert groups.