Brucella abortusstrain 19 vaccine became widely available in New Zealand in 1950. In 1966, vaccination was made compulsory and age restrictions were imposed. Surveys of the cattle population were carried out between 1966 and 1970 to establish the prevalence of brucellosis and to compare the performance of various diagnostic tests under New Zealand conditions. In 1969 and 1970 a voluntary test-and-slaughter scheme was introduced basedon the brucellosis card test as a screening test, the complement fixation test as the definitive test, and the milk ring test to screen accredited dairy herds. This scheme was extended to a compulsory national Brucellosis Eradication Scheme in September 1971, with the aim of bringing all eligible cattle under test by 1977.