We report the results of research on human leukocyte allo-antigen (HLA) and rheumatic fever (RF), the first published study to be carried out among Turkish children with RF. Ninety-three Turkish children, aged between 6 and 16 years (mean: 8 +/- 2.6), with RF participated in the study. Of the total, 26 patients had their first attack and 39 had acute rheumatic activity at the time of registration. The results demonstrate (1) negative but not significant association between HLA-A2 and RF; (2) a positive association between HLA-DR4 and RF (p less than 0.001); (3) a significant association between HLA-DR4 and carditis, but not with isolated arthritis. These results corroborate the concept of race-specific genetically determined familial susceptibility to the development of rheumatic heart disease.