The serum lipid and lipoprotein levels of 366 healthy children at preschool age are presented. The serum lipid and lipoprotein cholesterol concentrations vary with age. As compared to boys, a tending higher HDL-C and a tending lower T-C/HDL-C and LDL-C/HDL-C respectively were noted in girls. A higher HDL-C level has also been observed in Chinese children, as compared with North American children (P < 0.01).