Social class differences in New Zealand male mortality are investigated using two different systems of social class classification. In each case it is found that the lower social classes have mortality rates significantly higher than those of the upper social classes with the mortality rate of the lowest class being approximately twice that of the highest class on a six-category scale. The relative risk is higher in the younger age-groups. When the British Registrar-General's scale is used New Zealand exhibits a social class mortality gradient similar to that previously found in England and Wales, but the lowest social class experiences a particularly high mortality rate.