Cross-sectional data from 86 male and 59 female coastal Inuit of Igloolik (69 degrees 40'N, 81 degrees W) showed a steep age-related increase in the percentage of plasma n-3 fatty acids, with parallel trends in 20:5 and 22:6 but not 18:3 n-3 fatty acid concentrations. Omega-7 + 9 (p < .001) and omega-9 fatty acid concentrations (P < .001 in M, .008 in F) also decreased with age. A tundra-based Siberian indigenous population (30 male and 11 female nGanasan) had similar percentages of n-3 and n-6 fatty acids to the young Inuit, with little age-related change in either measure. Correlation matrices for the Inuit men showed quite strong negative associations of n-3 fatty acid percentages with total triglycerides (r = .34, p < .001) and phosphatidylcholine/free cholesterol ratio (r = -.36, p < .001). In the Inuit women, n-3 percentages were strongly related to phosphatidylcholine/free cholesterol ratio (r = -.60, p < .001), but not to triglyceride readings. The phosphatidylcholine/free cholesterol ratio was also correlated with n-6 percentages (r = -.55, p < .001). In the nGanasan men, triglyceride levels were correlated with n-6 (r = -.35, p < .050), but the size of the female sample was insufficient to establish useful correlations. The present data suggest that as the younger coastal Inuit are abandoning their traditional country foods, plasma levels of n-3 fall. Reasons why n-3 fatty acid levels are negatively related to the plasma phosphatidyl choline/free cholesterol ratio merit further investigation.