The hospital records of 7 patients with severe bronchopulmonary dysplasia (BPD) were reviewed. All patients were ventilator dependent for prolonged periods (mean duration intermittent mandatory ventilation (IMV) 14.3 ± 3.5 months) but eventually were successfully weaned from mechanical ventilation and sent home. The early phase of the disease was characterized by excessive CO2retention, tachypnea, and inability to tolerate reductions in IMV. A turning point was reached halfway through the course of mechanical ventilation (7.3 ± 1.4 months) which was identified by a persistent and significant reduction in Paco2and spontaneous respiratory rate. Thereafter, gradual reductions in IMV were generally well tolerated. Average monthly weight gain was less prior to the turning point than it was subsequently.