Mycobacteriosis is an important disease of poultry, companion birds and wild (including captive) birds. Mycobacterium avium complex (MAC) and Mycobacterium genavense are the two most common isolates seen in birds. Both these isolates also have zoonotic potential. Post mortem diagnosis of avian mycobacteriosis is straight forward, but ante-mortem diagnosis is difficult as clinical signs, haematology and biochemical changes are non-specific and can mimic other disease processes. Acid-fast staining of faeces is also problematic as faecal shedding of these organisms can be intermittent and differentiation of pathogenic versus non-pathogenic species of mycobacteria is not possible. In birds routes of infection are most commonly via ingestion, but aerosol and cutaneous routes of infection are also reported. A search of out post mortem database revealed 7/6631 (0.001%) cases of mycobacteriosis in four different species of wild bird. Three birds, a Southern Giant Petrel and two Blue Penguins had severe respiratory mycobacteriosis; the two Blue Penguins were from the same captive institution. Two birds were Weka, both from the same captive institution; one bird had focal involvement of the small intestine while the other bird had generalised involvement of the intestine as well as microscopic lesions in the liver and spleen. Two birds were Australasian Harriers; one bird, from a Rehabilitation facility, had generalised mycobacteriosis, with lesions in the gastrointestinal tract, spleen, lungs, skin and bone, while the second bird, which was wild, had cutaneous lesions around the feet. Mycobacterium avium complex (MAC) was isolated from the lung of one of the Blue Penguins and culture results from one of the Weka are pending. A diagnosis of mycobacteriosis in a captive facility poses logistic difficulties in terms of what to do with the remaining population of in-contact birds, as well as management practices to reduce the chance of zoonotic spread to staff.