HLA-A, -B, -C, and -DR typing was performed in a pedigree with familial polyposis coli (FPC). Three living members with FPC and one member without obvious FPC had the same HLA haplotype; A24(9)-B51-X-DRw8 (X indicates undetected HLA-C locus). It was genetically deduced that a deceased member with FPC also had this haplotype. No other members had this haplotype. No association was found between FPC and other HLA haplotypes. Thus an association between the specific HLA haplotype and FPC was suspected in this family.