A sensitive method for the analysis of the fatty acid composition of erythrocyte phospholipids with capillary column GLC is described. Under the assay conditions (base catalysed transesterification with sodium methoxide), only the fatty acids of the phospholipids are converted to their methylesters. The alkenyl ether chains of the plasmalogens are not transmethylated. This eliminates the need for thin layer chromatography for the separation of dimethylacetals and esterified fatty acids. The method is suitable for the measurement of the fatty acid patterns of erythrocyte phospholipids in small blood samples.