The aim of this study was to compare patterns of mortality in Australia and New Zealand, using routinely collected data. Life expectancy at birth is greater in Australia than in New Zealand (in 1996 the gap was 1.5 years for women and 1.1 years for men). Prior to 1970, mortality was lower in New Zealand than Australia. Possible reasons for the divergence in life expectancies include slower economic growth in New Zealand, more marked increases in economic inequalities which have affected Maöri in particular and, to a modest extent, differentials in health care.