Amyotrophic lateral sclerosis (ALS) is a disease causing degeneration of motor neurons, without any curative treatment. The most common cause of death is respiratory arrest due to atrophy of the respiratory musculature. ALS-associated respiratory insufficiency differs in mechanism from the more common causes of dyspnea, such as diseases of pulmonary or cardiac origin. Recognizing the respiratory insufficiency can be challenging for a clinician. It should be possible to predict the development of respiratory insufficiency in order to avoid leaving the treatment decisions concerning respiratory insufficiency to emergency services. Noninvasive ventilatory support can be used to alleviate the patient's dyspnea. It is actually recommended as the first-line treatment of ALS-associated respiratory insufficiency.