The lipid and fatty acid compositions and vitamin E content were analyzed in 48 human mature milk, 3 infant formulas (modified milk powder) and 8 market milk samples. The total lipid content in modified milk powder was similar those in human milk and market milk when total solids content of modified milk powder was corrected to that of human milk. In comparison with human milk, modified milk powder contained a lower proportion of triglycerides and higher proportions of phospholipids, free fatty acids and cholesterol esters. The ratios of phospholipids/triglycerides, total cholesterol / triglycerides and total tocopherol/total lipids in modified milk powder were significantly higher than those in human milk and market milk. The American recommendation for linoleic acid (0.7 IU/g) could be satisfied with human milk, modified milk powder and market milk. The proportions of short- and medium-chain even numbered saturates were higher and the proportions of long-chain derivatives of linoleic (${omega}6$ series) and linolenic (${omega}3$ series)acids were lower in modified milk powder and market milk than in human milk. It is concluded that in view of their levels in breast milk, the polyenoic derivatives of linoleic and linolenic acids must be taken into account when assessing infant foods.