Aspiration of exudate through an open perforation was performed in 183 patients with chronic otitis media. The pus was cultured aerobically and anaerobically. Aerobes only were isolated from 71 patients (39%); 20 patients (11%) had only anaerobes; and 91 patients (50%) had both aerobes and anaerobes. Only 1 specimen had no growth. There were 259 aerobic isolates. Pseudomonas aeruginosa was recovered from 68 patients. Other aerobes commonly recovered included Staphylococcus aureus and Klebsiella pneumoniae. There were 178 anaerobic isolates. Only anaerobic gram-positive cocci were isolated in 20 instances. Sixty-three Bacteroides isolates were recovered, including 12 Bacteroides fragilis group and 21 Bacteroides melaninogenicus.