Before ethical issues regarding prolonging life in patients with degenerative disease can be considered, the quality of life with medical intervention must be delineated. We have followed 15 patients with spinal muscular atrophy who have been treated with mechanical ventilation. They have received assisted ventilation for an average of 8 years 10 months (range 5 months to 23 years 10 months). Three of the patients required full-time ventilator assistance at the time of initiation of ventilation; the remaining 12 used nighttime ventilation for an average of 8 years 7 months. Nine patients continue to receive nighttime ventilation only. Two patients died after 5 years and 14 years of assisted ventilation, respectively. Of the 10 patients more than 18 years of age, three graduated from college, two are in college, three graduated from high school, and two completed eleventh grade. One patient is a mother of a healthy child. Two patients are employed, and two others have found fulfilling volunteer work. Ventilator support has not significantly interfered with these patients' plans and expectations.