Seven infants with wheezing and cyanotic spells were diagnosed as having tracheobronchomalacia by bronchoscopy or fluoroscopy. These studies demonstrated narrowing of the central airways by 75% or more on exhalation. Five patients were premature infants who had been ventilated for hyaline membrane disease. The mean time from onset of symptoms to diagnosis was six months. Determination of the optimal positive end-expiratory pressure (PEEP) during fluoroscopy facilitated subsequent management. Six of the seven patients required PEEP of 8 to 18 cm H2O for at least three months, and five of the seven still require mechanical ventilation. All patients improved, with decreased cyanotic spells and a reduced requirement for ventilatory support. Tracheostomy without PEEP did not appear to be helpful. Tracheobronchomalacia may be more frequent than usually appreciated; the treatment of choice appears to be long-term PEEP.