Parameters of Malécot's isolation-by-distance model are estimated for biological (anthropometric head and body dimensions, morphometric dimensions of metacarpal bones, quantitative and qualitative dermatoglyphic traits, and physiological/cardiorespiratory/variables) and linguistic distances and migrational kinship on the island of Korcula and the Peljesac peninsula in Middle Dalmatia, Croatia, Yugoslavia. Resulting parameters and the fit of the model are compared, for both regions, as well as with results of similar analysis in other parts of the world. The fit of the model is highly significant for migrational kinship and linguistic distances and less so for biological traits. Differences between these two populations, which live under basically similar ecological conditions, are explained by variation in biological and sociocultural history.