Four cases of congenital pulmonary lymphangiectasis were observed during a five year period. This represents an incidence of 1.11 per 10,000 cases among alive newborns and of 53 per 10,000 cases among pediatric necropsias performed during the same period. One case was observed in the clinical context of a generalized hemangiolymphangiomatosis, another was associated to tetralogy of Fallot and the remaining two cases were associated to obstruction of pulmonary venous return. Although one of the pathogenic theories generally accepted in the formation of pulmonary lymphangiectasis points to the presence of either hypertension or obstruction of pulmonary venous drainage, it is possible that such situation is only circumstantial. Among 40 personal cases of obstruction of pulmonary venous return proved anatomically, only in the two cases presented were pulmonary lymphangiectasis demonstrated. The presence of dysplastic elements in pulmonary tissue in cases of lymphangiectasis suggests that a more possible mechanism is a primary defect in the development of pulmonary lymphatics.