Thirteen patients with localized granuloma annulare and 19 with the generalized form of the disease were typed for HLA antigens. The control group consisted of 70 matched apparently healthy subjects. No significant difference in the frequencies of the 26 tested antigens was revealed between patients with localized granuloma annulare and controls. Patients with the generalized form of the disease showed a highly significant increase in the frequency of HLA-Bw35 as compared with both controls and patients with the localized form of the disorder (P = 0.001 and 0.01 respectively). The results seem suggestive of a possible different pathogenesis of the two forms of the disease.