AbstractLung diffusing capacity was measured in 92 healthy Caucasian children (52 boys and 40 girls), ranging in age from 6 to 17 years, using the single breath carbon monoxide technique (DLCO). Multiple regression equations were developed to predict the DLCO value. Standing height, gender, weight, and age were significant factors in the prediction of DLCO. Sitting height was not a significant covariate when standing height was in the model, but it could replace standing height in the equation. Equations are presented for the calculation of predicted DLCO in children based on standing or sitting height, age, sex, and weight. Pediatr Pulmonol 1991; 10:267–272.