HLA-A, -B, -C and -DR antigens were determined in 70 unrelated Danish patients with idiopathic haemochromatosis. The frequencies of HLA-A and -B antigens compared to 1967 normal control subjects and the relative risk values (RR) were: A3, 80.0% vs. 26.9% (P less than 0.0001), RR = 10.9; B7, 60.0% vs. 26.8% (P less than 0.0001), RR = 4.1; B14, 10.0% vs. 4.5% (P = 0.03), RR = 2.4; B47, 4.3% vs. 0.5% (P less than 0.0001), RR = 9.7; A3, B7, 51.4% vs. 12.2% (P less than 0.0001), RR = 7.6; A3, B14, 10.0% vs. 1.4% (P less than 0.0001), RR = 7.7; A3, B47, 4.3% vs. 0.5% (P less than 0.0001), RR = 9.7. Six patients (8.6%) possessed none of these four typical antigens. There was no association between disease and the frequencies of HLA-C and HLA-DR antigens. The pattern of HLA-antigens associated with haemochromatosis in Denmark shows similarities to those reported both in Germany, being HLA-A3, B7 dominated, and in Brittany, Great Britain and Central Sweden, being HLA-A3, B14 dominated.