Abstract National death-rates from ischæmic heart-disease are significantly correlated with population frequencies of histocompatibility antigen HLA-8 and haplotype 1-8. Serum-cholesterol levels may also be correlated with population frequencies of HLA-8. Inexplicably high death-rates from ischæmic heart-disease and high levels of serum-cholesterol in Finland may be due to the combined effects of HLA-8 and W15. It is suggested that HLA-8 (and possibly W15) are linked to genes which predispose to hypercholesterolæmia and ischæmic heart-disease. These findings provide some support for immunogenetic hypotheses for vascular disease in man.