Assisted ventilation provided in various ways is the treatment of choice in patients with ALS and sleep-disordered breathing and respiratory muscle weakness. Nocturnal noninvasive ventilation (NIV) in the form of bilevel positive airway pressure devices that deliver different levels of positive pressure in inspiration and expiration is the mainstay of treatment in ALS patients with sleep-disordered breathing. Continuous NIV should be initiated for the following reasons: (1) the presence of symptoms related to respiratory muscle weakness, ie, dyspnea, orthopnea, disturbed sleep, morning headache, poor concentration, excessive daytime sleepiness (Epworth sleepiness scale > 9); (2) evidence of respiratory muscle weakness (FVC < 80% or sniff nasal pressure < 40 cm H2O); and (3) evidence of significant nocturnal desaturation on overnight oximetry or morning ear lobe blood gas Pco2 ≥ 6.5 kPa. NIV support improves quality of life and survival in patients with ALS with respiratory muscle weakness. It reduces the work of breathing, promotes gas exchange, improves sleep-disordered breathing, sleep architecture, cognitive function, and daytime symptoms of breathlessness and excessive sleepiness. One factor that may limit the efficacy of NIV and make patient adaptation and tolerance difficult is bulbar involvement. Failure of NIV due to failure to stabilize gas exchange and inability to tolerate, need for ventilation for > 20 h/d, and need to protect the airway from excessive secretions and chronic aspiration are indications of invasive ventilation through tracheostomy. Families should be included in discussions about the patient’s options when evaluating for need for tracheostomy, because much of the burden of caring for a patient receiving tracheostomy ventilation falls on them.