Data on ventilatory function with particular reference to forced vital capacity (FVC), forced expired volume in one second (FEV1), and FEV1 expressed as percentage of FVC (FEV1%FVC) were obtained in 1413 healthy Tanzanian school children aged between 8 and 18 years. All subjects were nonsmokers and had neither symptoms nor history of cardiopulmonary diseases. Subjects in this study were significantly smaller in stature (P less than 0.05) and had smaller FVC and FEV1 (P less than 0.001) compared to values reported in children of comparable age and stature in the west. Lung volumes could best be described as a power function of standing height (y = a.Hb). The power derived from ln FVC on ln H were 3.39 and 3.24 for boys and girls respectively, while the power derived from ln FEV1 on ln H were 3.11 and 3.03 for boys and girls respectively. Constructed prediction formulae gave FEV1 and FVC which showed good agreement with FEV1 and FVC computed from prediction equations based on a similar mathematical model for black children in the Caribbean.