• Aspiration of retropharyngeal abscesses was performed in 14 children. Cultures were taken from aspirates for aerobic and anaerobic bacteria, and all yielded bacterial growth. Anaerobes were isolated in all patients; they were the only organisms isolated in two patients (14%) and were mixed with aerobes in 12 patients (86%). There were 78 anaerobic isolates (5.6 per specimen). The predominant anaerobes were Bacteroides species, Peptostreptococcus species, and Fusobacterium species. There were 26 aerobic isolates (1.9 per specimen). The predominant aerobes were α- and γ-hemolytic streptococci, Staphylococcus aureus, Haemophilus species, and group A β-hemolytic streptococci. β-Lactamase production was noted in 16 isolates recovered from ten patients (71%). These included all isolates of S aureus, six of 18 Bacteroides melaninogenicus group (33%), and two of three Bacteroides oralis (67%). These findings demonstrate the major role of anaerobic organisms in retropharyngeal abscesses and the presence of β-lactamase–producing organisms in two thirds of the patients.