Tuberculosis due to Mycobacterium bovis is an important problem in most species of farmed and wild cervids, including axis deer, fallow deer, roe deer, mule deer, sika deer, as well as red deer/elk/wapati. Deer appear to be unusually susceptible to M bovis infections. M avium infections may produce similar lesions. M tuberculosis infection is uncommon. Tuberculous lesions may be confined to isolated lymph nodes of the head, or they may be found extensively in lymph nodes and organs after a rapid, fulminating disease course. Abscessation in deer should always raise suspicions of tuberculosis. A presumptive diagnosis may be made using the tuberculin skin test and/or by in vitro cellular assays (blood lymphocyte immune-stimulation test or γ interferon assay), or a combination of these tests. Infection should be confirmed by an organism-based test.