Tracheomalacia is defined as increased dynamic collapse of the tracheal wall producing clinical symptoms. The clinical features of tracheomalacia depend on the location, length, and severity of the weakness of the tracheal wall. The diagnosis is made by fiberoptic bronchoscopy in a spontaneously breathing child, and severity is based on the degree of tracheal collapse with mild <70|X% collapse, moderate 70|X% to 90|X%, and severe >90|X% collapse with exhalation. Primary tracheomalacia is an uncommon congenital malformation of the tracheobronchial cartilage that is usually mild and self-limited. Primary tracheomalacia is often associated with other abnormalities of cartilage development. Acquired tracheomalacia has been more frequently recognized in recent years, in part because of the increased survival of the smallest prematurely born infants who require long-term endotracheal intubation. Although acquired tracheomalacia can result from long-standing extrinsic compression of the trachea, in infants with congenital heart disease or bronchopulmonary dysplasia, it is more commonly due to intrinsic weakening of the cartilaginous airway support. Most tracheomalacia resolves over time and without the need for intervention. Therapeutic intervention is indicated when there is recurrent hypoxemia with respiratory distress and growth failure. The therapy of tracheomalacia has included respiratory support with continuous positive airway pressure, surgical intervention such as aortopexy or vascular repositioning, and, in some cases, medications such as cholinergic agonists and avoidance of bronchodilator medications.