Twenty-nine anaerobic isolates were recovered from 28 pediatric patients with anaerobic bacteremia: 14 Bacteroides sp (11 in the B fragilis group); four anaerobic Gram-positive cocci; four Clostridium sp; four Propionibacterium acnes; and three Fusobacterium sp. No aerobic bacteria were isolated from these patients. The gastrointestinal tract was the possible portal of entry in 13 instances, eight of which were due to Bacteroides organisms, four to Clostridium sp, and one to F nucleatum. The ear, sinus, and oropharynx were probable portals of entry in seven instances, four of which were due to Peptococcus sp and two to Fusobacterium sp. Five patients (18%) died; four had bacteremia caused by B fragilis group, and one had bacteremia caused by P acnes. The average duration of antimicrobial therapy was 20 days (range, seven to 72 days). The early recognition and rapid institution of appropriate antimicrobial and surgical therapy are of utmost importance in improving the outcome of these patients.