Cardiovascular mortality rates (MRs) for 1970 were calculated from Department of Statistics reports for the various populations of the RSA and showed that the MRs for chronic rheumatic heart disease were highest in Coloureds and lowest in Whites, the rates for Asians and Blacks being intermediate, and that a relatively high proportion of all cardiovascular deaths in the 15- 24-year group were due to this disease. It was also found that the pattern of cardiovascular diseases differed in the various population groups as follows: in White males the MRs for ischaemic heart disease (IHD) were high (4 times the rate for cerebrovascular disease (CVD). In White females the MRs for IHD and CVD were similar and accounted for most deaths from cardiovascular disease. The MRs for hypertensive disease were low in Whites. Asians in the older age groups had the highest MRs for IHD, CVD and hypertensive disease of all the population groups. The MRs for IHD of Asians in general exceeded those of Whites. Coloureds had high MRs for CVD, relatively high MRs for hypertensive disease and other forms of heart disease (mainly ill-defined heart disease) and relatively low MRs for IHD (compared with Asians and Whites). Blacks had high MRs for CVD and other forms of heart disease (mainly ill-defined heart disease), relatively high MRs for hypertensive disease and very low MRs for IHD. The MRs for cardiovascular diseases in Blacks are not reliable.