Achalasia is a rare motor disorder of the oesophagus, characterised by the absence of peristalsis and impaired swallow-induced relaxation. These motor abnormalities result in stasis of ingested food in the oesophagus, leading to clinical symptoms, such as dysphagia, regurgitation of food, retrosternal pain and weight loss. Although it is well demonstrated that loss of myenteric oesophageal neurons is the underlying problem, it still remains unclear why these neurons are preferentially attacked and destroyed by the immune system. This limited insight into pathophysiology explains the fact that treatment is limited to interventions aimed at reducing the pressure of the lower oesophageal sphincter. The most successful therapies are clearly pneumatic dilatation and Heller myotomy with short-term success rates of 70-90%, declining to 50-65% after more than 15 years. The challenge for the coming years will undoubtedly be to get more insight into the underlying disease mechanisms and to develop a treatment to restore function.