Pain in amyotrophic lateral sclerosis (ALS) is paradoxical in this disease of the upper and lower motor neurons. As such, it remains an underestimated and neglected clinical problem because it is poorly identified by physicians, its mechanisms are numerous and its treatments are generally not effective. Pain may be primary in the form of cramps, spasticity and neuropathy, or secondary as nociceptive pain, and may arise before the first motor symptoms. It may also lead to depression and, in all cases, affect patients’ daily activities and quality of life. Given the high frequency of pain in ALS, the use of analgesic or sedative drugs is necessary and should reduce the course of the disease. Nevertheless, it is important to understand the pathophysiological mechanisms of pain in ALS, and to train physicians how to detect ALS pain early on and provide dedicated treatments. In France, the implementation of ALS centers is a positive response to the public-health problem resulting from this disorder.