Plasma phospholipid fatty acid concentrations have been measured in 735 individuals 12-89 years old. The absolute concentrations of palmitic, stearic, oleic, linoleic, dihomo-gammalinolenic, arachidonic, eicosapentaenoic, docosapentaenoic and docosahexaenoic acids increased from the third to the fifth decade of life, thereafter remaining fairly constant into the ninth decade. Alpha-linolenic acid showed no change. When expressed as g 100 g-1 fatty acids, palmitic, stearic, and linoleic acid decreased from the third to the fifth decade of life, dihomo-gammalinolenic and arachidonic acid remained unchanged, while the relative concentrations of long-chain n-3 fatty acids increased in a similar manner as when expressed in absolute concentrations. The results indicate that old age in itself has only a minor impact on the availability of n-3 fatty acids in the elderly. Factors such as living area and eating habits probably have a much more profound effect on their availability, also in old age.