Respiratory failure is the leading cause of death in patients with amyotrophic lateral sclerosis (ALS). We review the physiology of respiratory compromise in ALS and techniques of monitoring respiratory function. Treatment options, including pharmacologic interventions, aspiration precautions, and invasive and noninvasive modes of mechanical ventilation are reviewed. Our clinical experience with respiratory failure in ALS demonstrates significantly prolonged survival in subjects who elect to receive noninvasive mechanical ventilation (19.25 vs. 80.4 days, p < 0.01). Four of 18 patients who elected to receive noninvasive ventilation decided to discontinue treatment. Four of 13 patients who were receiving mechanical ventilation elected to discontinue life support. The decision to utilize these modalities must be made with realistic considerations of the patient's quality of life.