138 Blood samples and 12 hair samples from the district of Angmagssalik, East Greenland, have been analysed for selenium and mercury. It was found that selenium like mercury, was absorbed in accordance with the amount of marine food eaten. The mean blood concentration in the group eating most marine food was 173 and 186 micrograms Hg/1 for men and women, respectively, while in the group eating the lowest quantity of marine food, the mean values were 86 and 118 micrograms Hg/1. In blood, the selenium and mercury did not correlate in individuals, but only in groups according to eating habits. On a molar basis, selenium is present in blood in excess as compared to mercury, while the opposite is the case for hair. It is concluded that only part of the selenium interacts with mercury, and that blood, but not hair, reflects present dietary intake. The righ supply of selenium in relation to mercury exposure through the traditional arctic food is probably able to alleviate the hazards from dietary mercury exposure.