Ventilatory pulmonary function was investigated in 160 children and adults with repaired or unrepaired congenital cleft palate in comparison with 130 normal children and adults. Pulmonary function tests included measurement of lung volumes, of maximal voluntary ventilation (MVV) and of forced spirometry parameters: forced vital capacity (FVC), forced expiratory volume in 1 second (FEV1), FEV1/FVC ratio and mean forced expiratory flow during the middle half of FVC (FEF25-75). Patients with cleft palate demonstrated significant differences from normal individuals in some of the measurements made. Functional alterations were observed at higher frequency among adult patients with unrepaired clefts and mainly consisted of a reduction in expiratory flows and MVV. However, the deviations observed were usually discrete and probably of low physiopathologic significance. The results permit us to conclude that, in contrast to data reported by others, subjects with congenital cleft palate have little impairment of pulmonary ventilatory function.