High-performance liquid chromatography was evaluated for the rapid identification of Bacteroides species of clinical interest. Each isolate was inoculated into a defined chemical medium containing primarily carbohydrates and was incubated aerobically at 37 degrees C for 1 h. After centrifugation, the supernatants were placed on ice to stop further enzymatic reactions. Specimens were injected into an Aminex HPX-87H column in order to determine carbohydrates and acid metabolic products. Peak areas of carbohydrates for each isolate were compared with those for uninoculated medium. As the utilization indexes of raffinose, lactose and arabinose were found to be particularly significant, the patterns of carbohydrate utilization could be used for the identification of Bacteroides species. This method can be adapted for diagnostic laboratory use and has good potential for automated microbial identification.