Pulmonary Alveolar Proteinosis (PAP) is a rare entity characterized by the intra-alveolar accumulation of proteinaceous PAS positive and diastase resistant material. Its pathogenesis remains unclear, although a surfactant protein B deficiency and changes in the granulocyte-macrophage colony stimulating factor (GM-CSF) receptor have been proposed as involved mechanisms. Clinically two forms of PAP occur in the pediatric age group: acquired and congenital. The congenital form, very rare, presents in the neonatal period with respiratory insufficiency that starts in the first hours of life and is rapidly progressive, despite therapeutic measures. A definitive diagnosis is based on characteristic histological and immunohistochemical findings of pulmonary samples obtained by lung biopsy. The authors report on a case of Congenital Pulmonary Alveolar Proteinosis that is not associated with SP-B deficiency.