The concentrations of trace elements in hair were measured in 108 healthy subjects (60 males and 48 females, mean age 46-years) resident on Atafu (Tokelau) and in 83 subjects (63 males and 20 females, mean age 26-years) living on Kitava island (Papua New Guinea). On Kitava, a traditional subsistence lifestyle uninfluenced by Western dietary habits is still maintained, but on Atafu the dietary habits have been modified by the inclusion of such imported foods as rice, flour, sugar and canned meat and fish. The concentrations of zinc and magnesium in hair were significantly higher in the Kitava than in the Atafu subjects, whereas those of copper were similar in both groups, and those of selenium, mercury, lead and cadmium were higher in Atafu subjects. The levels of serum copper, magnesium and selenium concentrations in Kitava subjects were not so low as to indicate any trace element deficiency. The higher hair content of mercury, lead and cadmium found among Atafu subjects might be due to consumption of marine foods contaminated with metals, consumption of canned foods, or frequent cigarette smoking, though it is difficult to single out any specific factor.