We have determined the slipping point and the solid fat content (SFC) of lipids in human colostrum (3-5 days postpartum), mature milk (25-44 days postpartum), and some conventional infant formulae. Slipping points were 26.7°C in colostrum and 23.4°C in mature milk. Although the slipping point in one infant formula was higher than that in mature milk, those in others ranged from 20.0 to 22.5°C, which is lower than that in mature milk. Between 10°C and 25°C, the SFC of colostrum was 2% higher than that of mature milk. Lipids in colostrum and mature milk were in the liquid phase over 30°C. SFCs of infant formulae were similar to those of human milk.