Esophageal achalasia is a primary esophageal motility disorder characterized by the absence of esophageal peristalsis and failure of the lower esophageal sphincter to relax in response to swallowing. These abnormalities lead to impaired emptying of food from the esophagus into the stomach with resulting food stasis. Most patients experience severe dysphagia, and regurgitation can lead to aspiration and respiratory problems. Consequently, the quality of life of patients affected by achalasia is severely impacted. A thorough evaluation with upper endoscopy, barium swallow, and esophageal manometry is mandatory to establish the diagnosis and plan the optimal treatment. In selected patients, an ambulatory pH monitoring is recommended to distinguish between gastroesophageal reflux disease and achalasia.