A nationwide survey to monitor the susceptibility of the Bacteroides fragilis group, which began in 1981, was continued during 1987. In addition to the eleven drugs evaluated in 1986, sulbactam, a potent beta-lactamase inhibitor, was tested alone and in combination with ampicillin and cefoperazone. Imipenem, ampicillin/sulbactam, cefoperazone/sulbactam, and ticarcillin/clavulanic acid were the most active newer drugs tested, with less than 1% resistance rates. Chloramphenicol, metronidazole and clindamycin also had excellent activity with resistance rates of 0%, 0%, and 3% respectively. Resistance rates to cefoxitin remained stable at 8%. Ceftizoxime and cefotetan had resistance rates of 26% and 29%, respectively. Rates of resistance varied among different institutions and between the various species.