Achalasia is a primary esophageal motility disorder defined by lack of peristalsis and relaxation of the lower esophageal sphincter. This leads to obstructive symptoms (dysphagia and regurgitation) with consequent weight loss and other symptoms. A complete work-up is mandatory to a correct diagnosis, exclusion of other diseases and therapeutic planning. An upper digestive endoscopy, barium swallow esophagram and esophageal manometry are mandatory tests. Endolumenal functional lumen imaging probe is a more recent technology still in evaluation.