Trends in death certification rates for 12 major cancer sites and total cancer mortality in Argentina were analysed for the period 1966-91 on the basis of the World Health Organization database. In the late 1960s, total cancer mortality rates in Argentina (184/100,000 men, 117/100,000 women, world standard) were among the highest in the world. Over the 25-year period considered, however, cancer mortality in Argentina declined by 15% in both sexes, to reach 157/100,000 in men and 99/100,000 in women, for 1990-91. These rates were somewhat lower than those of North America and, particularly for women, relatively low on a worldwide scale. The favourable trends, observed mostly between the 1960s and the 1980s, reflect the steady decline in gastric cancer rates in both sexes, together with some decline in oesophageal, lung and other tobacco-related neoplasms, mostly in men, following some decline in tobacco consumption over the last two decades. The fall in oesophageal cancer may be related to decreased consumption of hot maté, too. Colorectal cancer rates were high in the 1960s, but declined by 17% in men and 35% in women. An approximately 50% decline was observed for skin cancer mortality, which was among the lowest in the world in the early 1990s, and some decline was observed also for leukaemias and uterine cancer, while breast and prostate neoplasms showed a general stability. The two major unfavourable features of cancer mortality in Argentina were the persistently high rates for oesophageal in men, and for uterine cancer mortality in women. These are likely a result of hot maté drinking for oesophageal cancer and inadequate screening for cervical cancer.