The carbohydrate content of breast milk was investigated by capillary gas liquid chromatography. The milk samples obtained from 16 normal lactating mothers contained glucose, galactose, lactose, and 3-fucosidolactose. The content of monosaccharides in breast milk was 2-12 times higher than that in cow's milk. The lactose content amounted to 84-95%, whereas the ratio of alpha- tox beta-froms was within 0.92-0.95%. Breast milk was found to contain alpha- and beta-forms of 2- and 3-fucosidolactose which do not occur in cow's milk. The content of these forms accounted for 3%. The biological role of breast milk carbohydrates is discussed.