Three of six captive South American coatis (Nasua nasua) presented with respiratory distress and died despite treatment. Postmortem examination performed on two of these animals revealed granulomatous pleuropneumonia associated with acid-fast bacilli. Because of the possible diagnosis of mycobacterial infection, the three remaining asymptomatic coatis were anesthetized. Tracheal washes were sampled and submitted for microbiology, and the animals were euthanatized and postmortem examinations performed. One of these asymptomatic adult males had whitish granulomas in multiple organs and tissues. Additionally, the isolate from this male's tracheal wash was identified as Mycobacterium kansasii by molecular analysis. To the authors' knowledge, this is the first report of M. kansasii infection in Nasua nasua.