An 18-yr-old man with Duchenne muscular dystrophy and ventilatory failure could not be weaned from mechanical ventilation using a T-piece method, despite repeated attempts over 3 months. Subsequently, we weaned the patient using inspiratory muscle resistive training (IRT), modified by the concurrent delivery of intermittent mandatory ventilation (IMV). During the training program, the sessions were gradually prolonged from 5 min to a maximum of 30 min, the IMV rate was gradually decreased, and the magnitude of the resistive load was gradually increased. After 45 days of training, his vital capacity had increased from 380 to 850 ml, his maximal inspiratory airway pressure from -28 to -50 cm H2O, and his tolerance of T-piece breathing, from less than 10 min to over 16 h. After an additional 2 wk of nocturnal mechanical ventilation, he was successfully weaned. We conclude that IRT with IMV can be an effective method of weaning patients who have severe ventilatory failure.