Achalasia is a neurodegenerative motor disease of the esophagus resulting mainly from a loss of function of the lower esophageal sphincter, the pathophysiology of which is still poorly understood. Its incidence is rare-it is 1.6 per 100,000-and its occurrence in the context of paraneoplastic syndrome has been rarely described in the literature. We report a rare case of paraneoplastic achalasia associated with lung cancer.