The authors performed HLA typing in 18 patients affected by neurofibromatosis (NF) and in 13 of them they also typed all the available members of their families. In 9 families manifesting a kindred occurrence further 16 patients, in whom the disease had not yet been diagnosed, have been unveiled. In 8 families our of nine manifesting a familial load of the disease there was agreement in one HLA haplotype eventually HLA identity among the diseased sibling members. From this point of view it appears that HLA typing in NF might be a valuable contribution especially for the diagnosis of the complete cases in families manifesting a kindred type of NF occurrence. Since NF is a disease perilous through its life endangering complications of a malignant character the authors recommend its dispensation and a concentration of all the NF affected patients and their relatives into a limited number of clinical establishments endowed with a possibility of cooperation with some HLA laboratory.