Close correlation between HLA antigens and haplotypes and familial polyposis coli, an infrequent inherited condition which results in an early onset of colonic adenomas and carcinoma is reported. Similarity between the patients' group and their healthy relatives is recorded, both groups differing from a healthy control group (HLA B35, DR5). This haplotype cannot be considered as a marker of the disease but provides a statistical indication of a high risk of adenomas in each family affected by FPC.