Obesity is an anomaly of body build characterized by excessive growth in dimension through the accumulation of subcutaneous fat. If this occurs in a fully grown person, the only distinguishing feature will be the increased circumference and the excessive weight. During childhood, however, when growth is a normal process, the problem arises as to how obese children compare with normal ones with regard to those phases of growth which are not expressed by weight.The growing-up process is complex; it includes dimensional growth and differentiation. The first is commonly measured in a simple way, by the increase in weight and stature. The second can be assessed from the structural progress in skeletal development as visualized in roentgenograms. During later childhood and the preadolescent period the appearance of secondary sexual characteristics is an indication of progressing biologic maturation.Though the literature on obesity in childhood is extensive, the problem of studying obesity as a variety of growth and development has not been dealt with systematically in previous publications. The reports which refer to the special conditions of obesity during the growth period discuss the subject as it applies to individual observations and as a more or less incidental finding.Czerny and Keller,1 citing the older literature and referring to their own observations, drew attention to the fact that obese children fre-This investigation has been aided by a grant from the Josiah Macy, Jr.Foundation.