Despite the availability of effective control measures, simian tuberculosis continues to be a major colony management problem. In 1972, 909 cases of simian tuberculosis were reported to the Center for Disease Control. Most of the cases (838) were in rhesus monkeys (Macaca mulatta). The attack rate was higher for animals conditioned by commercial importers prior to sale (6.6%) than for animals received shortly after importation without conditioning (1.2%) . Failure to apply control measures effectively and consistently both in trade channels and at the user level is a significant factor in peptuation of the problem.