Changes in fatty acid composition of phospholipids from human milk during the course of lactation were determined in milk from Korean lactating mothers giving birth at term. The levels of 8 : 0 increased significantly from colostral to transitional stages with a further small decrease at mature stage. The proportions of 10 : 0, 12 : 0 and 14 : 0 increased markedly from colostrum to transitional to mature milk. The w6-derived long-chain polyunsaturated fatty acids, 20 : 2w5, 20 : 4w6 and 22 : 4w5, were decreased with time of lactation. The levels of 24 : 1w9 were significantly higher in transitional milk than in colostrum and then significantly decreased to lowers than the colostral levels at mature milk.