Gene frequencies from a sample of Orkney islanders relating to red cell blood groups, red cell isoenzymes, serum proteins and HLA types indicate that the Orcadians are situated at the extreme of the European range in many systems. Genetic distance and principal components analyses of gene frequency and relationship matrices suggest that the closest Orcadian affinities are with the North Sea populations rather than with Atlantic. Though their genepool has been modified to some extent by immigrant genes, it is suggested that the Orcadians represent the remains of a relict population, in the same way as, but different from, those of the Gaelic fringe.