AbstractPulmonary hemorrhage and hemoptysis are uncommon in childhood, and the frequency with which they are encountered by the pediatric pulmonologist depends largely on the special interests of the center to which the child is referred. In those centers caring for children with cystic fibrosis or congenital heart disease, these will be by far the most common causes of hemoptysis. Other causes of hemoptysis are far less common, such as bleeding from localized lesions in the upper airway or tracheobronchial tree. Even less common is bleeding into the lungs as part of a systemic disease, usually with renal involvement (pulmonary‐renal syndromes), such as systemic lupus erythematosis or Goodpasture's syndrome. Bleeding into the lungs in children with a bleeding diathesis probably only occurs in immunosuppressed children after transplantation. When no other cause is found for pulmonary hemorrhage, the presumed diagnosis is idiopathic pulmonary hemosiderosis. This review discusses the various causes of hemoptysis and pulmonary hemorrhage, and the appropriate investigations to aid in determining the correct diagnosis. The management and prognosis of idiopathic pulmonary hemosiderosis, based on cumulative experience from published reports, are considered in more detail. Pediatr Pulmonol. 2004; 37:476–484. © 2004 Wiley‐Liss, Inc.