Pediatric cardiopulmonary resuscitation drug therapy is based upon body weight, a statistic that often requires estimation. Using two current techniques of estimating body weight and the devised weight-estimating method (DWEM), the authors estimated the weights of 258 children. The DWEM, which is based on body habitus and height, was more accurate than other methods (P less than 0.01). Using height, habitus, sex, and age in a multiple regression analysis, habitus and height--two readily available measurements--were the best predictors of body weight. The DWEM, based on these two measurements, is a simple method of estimating children's weights and is more accurate than currently used body-weight estimations.