1. Serum proteins were studied in 106 children ranging from 3 to 14 years using a modification of Laurell's method of quantitative immunoelectrophoresis.
2. Quantitative values are given for eleven proteins, viz.: α1 lipoprotein, α1 antitrypsin, α1 easily precipitable glycoprotein, α1 group specific component, α2 macroglobulin, caeruloplasmin, haptoglobin, transferrin, haemopexin, β lipoprotein, and β1AC(C3).
3. There were no significant differences in protein levels between the sexes, and no correlation between age and protein level within the age range studied.
4. The values were also compared with those of infants aged 6–12 months, young adults of 16–25 years, and adults of 16–65 years.