In an attempt to evaluate the lung functions in patients with mitral valve disease, spirometric pulmonary functions were measured for 60 Egyptian children with isolated mitral valve disease. The restrictive pattern of pulmonary function was the commonest among the whole patients. Significant negative correlation was found between LVESV and both of MVV (p<0.05) and FEV1 (p<0.05). We observed normal pattern in some symptomatizing patients indicative of the need for other test to investigate the pulmonary function as exercise test. Spirometric test can be used as a screening test to discover the optimum time of surgical interference before occurrence of irreversible pulmonary vascular changes.