New Zealand has a large reservoir of Mycobacterium bovis infection in wild and farmed animals. This study aimed to assess the extent of human infection with this organism and the potential contribution of these animal sources. Combined epidemiological and laboratory investigation of human tuberculosis cases over the period 1995-2002 showed that M. bovis accounted for 2.7% (54/1997) of laboratory-confirmed human tuberculosis cases, a rate of 0.2/100,000 population. M. bovis isolates from humans (23) were typed using restriction endonuclease analysis (REA) and compared with isolates from wild and domestic animals (2600). Fourteen (61%) of the human isolates had REA patterns that were identical to patterns for isolates from cattle, deer, possums, ferrets, pigs, and occasionally cats. These results suggest a low level of ongoing M. bovis transmission from animal reservoirs to humans in New Zealand.