Achalasia is an uncommon esophageal motor disorder. It has been associated with other diseases such as Parkinson's disease and depressive disorders, but coincidence of achalasia and Down's syndrome is rare. We report five cases of achalasia in Down's syndrome patients seen in our institution. Two of the five cases were diagnosed at pediatric age. Respiratory symptoms and growth retardation were the main clinical manifestations in pediatric patients, whereas adult patients mainly complained of dysphagia. Taking into account the prevalence rate of both disorders, the association seems higher than that expected by chance. The possible etiopathogenic implications of this association, as well as its clinical relevance, are discussed.