The length of the trunk and its growth in children have been determined at yearly intervals during the last nine years of their growth from a longitudinal study of a series of boys and girls with normal spines. The amounts of growth in sitting height which remain at successive levels of maturity (skeletal ages) have been provided in both numerical and graphic form. These values show the average trend as well as the extent of variation at each age considered. This informations should help in the evaluations of the growth potential of individual children who may have some interference with the normal growth of their spines.