Achalasia is a rare motor disorder of the esophagus, characterized by the absence of peristalsis and impaired swallow-induced relaxation. These motor abnormalities result in stasis of ingested food in the esophagus, leading to clinical symptoms, such as dysphagia, regurgitation of food, retrosternal pain and weight loss. Etiology is unknown. Some familial cases have been reported, but the rarity of familial occurrence does not support the hypothesis that genetic inheritance is a significant etiologic factor. Association of achalasia with viral infections and auto-antibodies against myenteric plexus has been reported, but the causal relationship remains unclear. In terms of diagnosis, esophageal manometry is the gold standard to diagnose achalasia. Still, its role in post-treatment surveillance remains controversial. Radiological studies support the initial diagnosis of achalasia and have been proposed for detecting preclinical symptomatic recurrence. Although endoscopy is considered to have a poor sensitivity and specificity in the diagnosis of achalasia, it has an important role in ruling out secondary causes of achalasia. Treatment is strictly palliative. Current medical and surgical therapeutic options (pneumatic dilation, surgical myotomy, and pharmacologic agents) aimed at reducing the lower esophageal sphincter (LES) pressure and facilitating esophageal emptying by gravity and hydrostatic pressure of retained food and liquids.