Achalasia significantly affects patients' quality of life and can be difficult to diagnose and treat.To review the diagnosis and management of achalasia, with a focus on phenotypic classification pertinent to therapeutic outcomes.Literature review and MEDLINE search of articles from January 2004 to February 2015. A total of 93 articles were included in the final literature review addressing facets of achalasia epidemiology, pathophysiology, diagnosis, treatment, and outcomes. Nine randomized controlled trials focusing on endoscopic or surgical therapy for achalasia were included (734 total patients).A diagnosis of achalasia should be considered when patients present with dysphagia, chest pain, and refractory reflux symptoms after an endoscopy does not reveal a mechanical obstruction or an inflammatory cause of esophageal symptoms. Manometry should be performed if achalasia is suspected. Randomized controlled trials support treatments focused on disrupting the lower esophageal sphincter with pneumatic dilation (70%-90% effective) or laparoscopic myotomy (88%-95% effective). Patients with achalasia have a variable prognosis after endoscopic or surgical myotomy based on subtypes, with type II (absent peristalsis with abnormal pan-esophageal high-pressure patterns) having a very favorable outcome (96%) and type I (absent peristalsis without abnormal pressure) having an intermediate prognosis (81%) that is inversely associated with the degree of esophageal dilatation. In contrast, type III (absent peristalsis with distal esophageal spastic contractions) is a spastic variant with less favorable outcomes (66%) after treatment of the lower esophageal sphincter.Achalasia should be considered when dysphagia is present and not explained by an obstruction or inflammatory process. Responses to treatment vary based on which achalasia subtype is present.