Forty children with coeliac disease were subjected to HLA-A and B antigens typing using the two-way lymphocytotoxicity technique. An increase in the frequency of HLA-B8 and B12 was found in patients as compared to the control group. Family studies conducted in 4 selected families have indicated that four out of five siblings who inherited the HLA-B8 antigen from their parents have contracted coeliac disease. In one of the families both siblings had HLA-B8 but only one of them contracted coeliac disease. It is suggested that the association of coeliac disease with HLA-antigen could be multifactorial, i.e. the disease could be attributed to the presence of more than one antigen.