Anaerobic chambers and jars are used routinely in laboratories to grow anaerobic bacteria. Parallel quality control of Brucella Blood Agar was performed using the two procedures. Frequent failures in quality control were noted when using the anaerobe jar procedure. No quality control failures occurred when using the anaerobic chamber. Further studies indicate that these failures are not related to the method of providing anaerobic conditions, but to the preparation and inoculation of quality control organisms in the presence of air.