Aerobic and anaerobic bacterial flora of burn sites in 180 children were monitored. Specimens were obtained twice a week; each patient had between one and 21 cultures taken (mean 2.4). A total of 392 specimens were collected over 2 years, of which 319 were positive. Aerobic bacteria alone were present in 225 specimens (71%) and anaerobic bacteria alone were present in 26 (8%). Mixed aerobic and anaerobic bacteria were present in 68 burn specimens (21%). A total of 580 isolates (448 aerobes and 132 anaerobes) were recovered, accounting for 1.8 isolates per specimen (1.4 aerobes and 0.4 anaerobes). The predominant aerobic isolates were S.epidermidis, S. aureus, alpha hemolyticstreptococcus, Pseudomonas sp., and Group D streptococcus. The predominant anaerobic isolates were:P. acnes, anaerobic Gram-positive cocci, and Bacteroides sp. Blood cultures were drawn from 45 children: four showed bacterial growth of one of each of the following isolates:S. aureus, E. coli, Peptococcus asaccharolyticus, andB. fragilis. The numbers of isolates per specimen were higher in the oral and anal area (3.2 and 2.8) than in the extremities and trunk (1.8 and 0.9). Gram-negative enteric rods and Group D streptococci were more frequently recovered from the anal area.S. aureus, S. epidermidis, andP. acneswere more frequently recovered from extremities. Bacteroides sp. andFusobacterium nucleatumwere more frequently recovered from the anal and oral areas. All children were treated with local application of silver sulfadiazine, and antimicrobial therapy was used in 128 children. Statistical analysis showed no correlation between the bacteria isolated and use of antimicrobial agents. These data suggest a role for anaerobic bacteria in the colonization of burns in children, especially in burns of the anal and oral areas.