Subjects were randomly selected from existing lists so that six men and six women were selected from each age-year group from 30 to 69 broken down as follows: ages 30-34; 35-39; 40-44; 45-49; 50-54; 55-59; 60-64; 65-69. Plasma samples for these subjects were retrieved from storage in batches and analyzed. The prevailing distribution of fatty acids in the general population was calculated. The interrelationships were studied among levels of fatty acids, particularly w3 and w6 fatty acids, with lipoproteins and apolipoproteins. Relationships among fatty acid compositions of different lipid fractions were explored and their relationship with various cardiovascular risk factors were evaluated. Over 60 fatty acids were quantitated using capillary gas-liquid chromatography. Tables of reference values were produced for the general population and for selected subpopulations. Multivariate analysis was used to correlate fatty acids and other biochemical markers.