Racial differences in the temperature responses of fingers to local cooling have been studied by a number of investigators. A higher skin temperature during cold water immersion of a finger was shown in Orochons in Manchuria by YOSHIMURA and IIDA1), in Gaspe fishermen by LEBLANC et al.2), in British fish filleters by NELMS and SOPER3) and in Arctic Indians and Eskimos by MEEHAN4), ELSNER at al.5) and EAGAN6,7). A similar result was reported by MILLER and IRVING8) who measured the skin temperature of Eskimos during cooling hands in cold air. According to KROG et al.9), the onset of cold vasodilatation during cold water immersion of a hand was more rapid in Lapps and North Norwegian fishermen than in a group of control subjects, although the levels of hand blood flow were the same in these groups. It was also demonstrated by IAMPIETRO at al.10) that finger temperature during digital cooling was lower in Negroes than in control white. The responses are likely to depend not only on an inborn racial characteristics but also on previous cold experiences, as indicated by TAKAHASHI11), YOSHIMURA and IIDA1) and ADAMS and SmiTH12), and have been considered to be useful to assess the peripheral tolerance to cold13). Accordingly, we have attempted to compare the finger temperature responses to cold water immersion on several groups of subjects in Hokkaido, including Ainu, natives to Hokkaido. A part of this study was reported elsewhere14,15). METHODS The following 9 groups of subjects participated in this study. (a) Japanese subjects born on the main island of Japan: 46 male students and professionals in Sapporo. (b) Japanese subjects born on Hokkaido: 41 male students and professionals in Sapporo, 38 girl students in Asahikawa, 14 nurses in Asahikawa, 22 policemen in Asahikawa, 13 farmers in Huren, 23 fish factory workers in Monbetsu and 13 fishermen in Monbetsu.