Patients with chronic respiratory insufficiency resulting from paralysis of respiratory muscles have been supported most commonly by mechanical ventilation via a tracheostomy. Acute and long-term morbidity and mortality have been associated with tracheostomy. Noninvasive alternatives for providing mechanical respiratory support include negative pressure "body ventilators" and positive pressure ventilation via a nasal, oral, or oronasal interface. Intermittent positive pressure ventilation via the nose, mouth, or oronasal combination is effective and convenient for the majority of patients when the interface is sufficiently airtight and comfortable to permit effective long-term use. Construction of custom-fabricated interfaces for the administration of assisted ventilation is presented. These interfaces provide better fit for greater interface seal and comfort than commercial masks. They allow more patients to benefit from assisted positive pressure ventilation in the home without resorting to a tracheostomy.