The purpose of this study is to determine the relationship in college-aged women between somatotype using both Sheldon's ('69) and Heath and Carter's ('67) procedures, and body composition, as measured by whole-body 40K counting and body density. Sheldon's endomorphy is closely associated with height and weight; Heath and Carter's first component is significantly related to weight and body fatness. Lean body mass (LBM) as a weight or as a percent is not closely related to Sheldon's mesomorphy or Heath and Carter's second component. However, when LBM and height are used as independent variables to estimate somatotype, both variables are significantly related to Heath and Carter's second component, accounting for 61% of the variance. Thus Heath and Carter's second component is significantly associated with LBM for a given body height. Most of the variation in Sheldon's ectomorphy and Heath and Carter's third component can be accounted for by weight and height. Sheldon's somatotype for all three components is not as closely related to body composition as Heath-Carter's. Body composition, as measured by either 40K counting or body density, is found to be important in accounting for variation in Heath and Carter's first and second components.