A comparison of lymphocyte antigens showed that 32 of the 33 BoLA antigens defined at the third international BoLA workshop (Bull et al., 1989) corresponded to previously defined local antigens (Stear et al., 1988). The third workshop antigen w18 had no locally defined equivalent. All 32 antigens were shown in family studies to be expressed by autosomal co-dominant genes, and all 32 workshop antigens were shown to be products of the BoLA system. After excluding the supertypic antigens, nearly all animals tested possessed only one or two antigens and there were no observed recombinants in family studies. These results do not exclude the possibility that the 32 workshop antigens are the products of one locus (BoLA-A).