Achalasia is a primary esophageal disorder involving the body of the esophagus and lower esophageal sphincter affecting equally both genders and all ages. While its etiology remains unclear, the pathophysiologic mechanism involves the destruction of the myenteric plexi responsible for esophageal peristalsis. Given the slow, initially oligosymptomatic progression and relative low prevalence of disease, achalasia can remain undiagnosed for years. 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 pre-clinical 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 (i.e. pseudoachalasia). With respect to treatment, laparoscopic myotomy and pneumatic balloon dilatations of the lower esophageal sphincter are considered definitive treatments for achalasia. Both treatment options offer sustained clinical responses, with head-to-head trials being currently underway. Botulinum toxin injection in the lower esophageal sphincter is considered an acceptable alternative in patients who are not candidates for surgery or balloon dilatation or as proof of concept in difficult to diagnose patients. Pharmacologic therapies for achalasia offer mild, transient improvement at best. In summary, diagnosis achalasia requires shrewd history taking and dedicated esophageal testing. In experienced hands, treatment of achalasia can provide long-term sustained clinical improvement.