Bacterial septicemia occurred in 22 of 210 pediatric patients with sickle cell disease over a nine-year period, an attack rate of 10.5%. Children less than 2 1/2 years old with hemoglobin SS were at greatest risk; Streptococcus pneumoniae was the most common pathogen. Although sudden febrile illness developed in nine patients, in 13 a gradual prodrome was associated with symptoms for more than 24 hours before evaluation. Both initial body temperature and WBC count were highly variable. In all six fatal cases, autopsy disclosed adrenal hemorrhagic necrosis, which in three was diffuse and typical of that seen in the Waterhouse-Friderichsen syndrome. Recommendations in patients with sickle cell disease and fever, even if only of moderate degree, include the rapid initiation of antibiotic therapy and the use of corticosteroids at the first sign of circulatory insufficiency.