The objective of this study was to report the frequency of concurrent serious bacterial infections in infants and young children hospitalized for treatment of respiratory syncytial virus (RSV) lower respiratory tract infection. Data were collected through a retrospective review of the medical records of all 912 patients with a discharge diagnosis of RSV bronchiolitis or pneumonia between July 1, 2000 and June 30, 2002. Two (0.43%) of 470 patients tested had a positive blood culture; both patients were >90 days of age. None of 101 patients tested had a positive cerebrospinal fluid culture, and 28 of 234 (12.0%) patients tested had a positive urine culture. Routine sepsis and meningitis workups are not necessary in non-toxic-appearing infants and young children with RSV lower respiratory tract infection.