Muscle, liver and kidney samples of 20 species of birds, seals, whales and polar bear were analyzed for total and organic mercury. Organic mercury concentrations varied considerably between individuals. A general tendency towards age accumulation was found, together with log-linear correlations between organic mercury concentrations in the three tissues. The major part of the muscle mercury was organic (maximum concentration found was 1235 micrograms kg-1 wet wt). This also applied to liver of birds, while in mammal liver organic mercury concentrations approached a level of 2000 micrograms kg-1 wet wt, which was not exceeded even when the total mercury concentration was greater than 100,000 micrograms kg-1 wet wt. The percentage of organic mercury in relation to total mercury in kidney of seals and whales was 10-20% (maximum 982 micrograms organic mercury kg-1 wet wt), while in polar bear it was less than 6% (maximum 217 micrograms kg-1 wet wt). For the monitoring of local food in the Arctic, the simpler and less expensive analysis of total mercury suffices when testing muscle, whereas liver and kidney should be tested for organic mercury as well.