Mortality rates (MRs) per 100 000 for ischaemic heart disease (IHD) of White males and females in the RSA in the age group 15-64 years decreased substantially in 1980 compared with 1970, the male rates decreasing from 256,1/100 000 to 200,3/100 000 (-22%) and the female rates decreasing from 79,3/100 000 to 56,6/100 000 (-29%). In this period, the White male population increased from 1,20 to 1,48 million and the White female population from 1,18 to 1,45 million, but the number of deaths from IHD fell from 3 064 to 2 720 in males and from 936 to 756 in females. For the year 1980 MRs for acute myocardial infarction (AMI) and IHD in White males and females of the RSA were compared with the MRs of males and females in the USA, Australia, England and Wales, and Scotland. The MRs for both AMI and IHD of males in the USA and Australia fell well below the figure for England and Wales, which contrasted markedly with the situation in 1970. The MRs for AMI and IHD of males in Scotland and the RSA were similar and were much higher than the MRs of males in the other countries. The MRs for AMI and IHD of females in the USA, Australia, and England and Wales were similar and well below the MRs of females in Scotland and the RSA, the MRs of females in Scotland being higher than the MRs of females in all the countries studied.