The concentration of lead in 175 blood samples originating from the district of Angmagssalik, East Greenland and 130 from Aarhus, Denmark, has been determined. Both Greenland and Danish males had significantly higher (5%) blood lead than females (Eskimoan males 14.8 micrograms Pb/100 ml, females 12.8 micrograms Pb/100 ml; Danish males 10.5 micrograms Pb/100 ml, females 7.7 micrograms Pb/100 ml). For Danes living temporarily in Greenland the values were: males 10.5 and females 10.2 micrograms Pb/100 ml. Eskimos of both sexes were found to have higher blood lead values than Danes living in the same area. Danish males from Greenland and Denmark were not found to be different, whereas Danish women living in Greenland had a significantly higher (5%) mean value than women living in Denmark. In the Eskimo group, but not in the Danish, a weak, positive, but significant age correlation was found. 4 samples of Eskimo origin exceeded 35 micrograms Pb/100 ml accepted in the EEC as a maximum value for non-occupationally exposed persons. When re-examined 5 months later, all values were below this limit. The influence of eating habits (local or imported food) and smoking habits was tested, but not found to influence the blood lead concentration. The results have confirmed that blood lead levels in Greenland are comparable to those found in European industrialized areas. The reason for the unexpected high level in the arctic area with minimum car driving and industry remains to be clarified.