BACKGROUND: Impaired cough secondary to weakness from neuromuscular disease (NMD) can cause serious respiratory complications, including atelectasis, pneumonia, small airway obstruction, and acidosis. The mechanical in-exsufflator (MI-E) delivers a positive-pressure insufflation followed by an expulsive exsufflation, thereby simulating a normal cough. Use of the MI-E in adults with impaired cough results in improved cough flows and enhanced airway clearance. However, only limited reports of MI-E use in children exist. OBJECTIVE: To determine the safety, tolerance, and effectiveness of the MI-E in a pediatric population. METHOD: Retrospective medical record review. PARTICIPANTS: Sixty-two patients (34 male patients) observed in a pediatric pulmonary program with NMD and impaired cough in whom MI-E therapy was initiated. Median age at initiation of MI-E use was 11.3 years (range, 3 months to 28.6 years). Diagnoses included the following: Duchenne muscular dystrophy (17 patients); spinal muscular atrophy, types I and II (21 patients); myopathy (12 patients); other nonspecific NMD (12 patients). Mechanical ventilation via tracheostomy was used in 29 patients, and 25 patients used noninvasive ventilation. RESULTS: The median duration of use was 13.4 months (range, 0.5 to 45.5 months). One infant died before using MI-E at home. Five patients chose not to continue MI-E therapy. Complications were reported in two patients, but ultimately they used the MI-E device. Chronic atelectasis resolved in four patients after beginning MI-E therapy, and five patients experienced a reduction in the frequency of pneumonias. CONCLUSION: In 90% of our study population, the use of an MI-E was safe, well-tolerated, and effective in preventing pulmonary complications.