To assess the utility of blood cultures in the management of uncomplicated pyelonephritis in women, we prospectively collected data from 583 cases. Discordant cases were defined as those for which the pathogens isolated from urine and from blood were different. We found that 97.6% of cases were nondiscordant. Clinical and microbiological evolution of infection did not differ between the 2 groups, and no changes of antibiotic therapy were required on the basis of blood culture results. Blood culture may not be routinely required for the evaluation of uncomplicated pyelonephritis in women.