Forty-one patients with Hashimoto's thyroiditis (HT) and 82 with Pernicious anaemia (PA) were investigated. All 123 patients were HLA-D typed and results correlated to thyroglobulin antibodies (TgAB), microsomal antibodies (MAb), parietal cell antibodies (PCA), circulating immune complexes (IC), and intrinsic factor antibodies (IFA). In PA, TgAb was found less frequently in Dw2 positive patients than in Dw2 negative patients. IFA was rarely found in Dw5 positive PA patients. In HT, patients positive for Dw5 had lower levels of TgAb. IC were present in 67% of patients with HT, but only in 2.5% of patients with PA (p less than 0.01). Dw5 was associated with low levels of IC in HT. In conclusion, HT and PA seem to be related by their association with HLA-D types, but a heterogeneity in the pattern of antibodies and IC could be seen. The organ specific antibodies characteristic for each disease were present in lower levels in patients with Dw5.