In achalasia of the oesophagus conservative treatment by dilatation should be tried before any kind of surgical intervention is advised. In a case in which Heller’s operation failed (probably owing to defective technique), cure was obtained by dilatation. In another case death unexpectedly followed Heller’s operation. Out of 60 personal cases of this condition, the Starck dilator was used with success in the first five. The remaining 55 cases were treated with the McCarthy pneumatic dilator with immediate good results, the improvement lasting up to 15 years. In two cases dilatation had to be repeated a month later, when success was immediate. These two initial failures are attributed to error in placing the dilator balloon. Dilatation is now carried out without anaesthesia, the patient, fasting, having previously ingested 50 c.c. of opaque medium for the better control of the location of the dilator balloon. The patient stands during the procedure, and fluoroscopic screening is performed at the same time. The operation lasts from three to five minutes. At the moment when dilatation is effected, the patient usually experiences a tearing pain of short duration, and this may be followed by a retrosternal aching lasting from one to six hours. The use of antibiotics on the day of operation and the two following days is considered to be of great value. Nothing should be given by mouth during the first three hours after intervention, and then only liquids to the end of the second day. Soft foods are given for the next three days, and after that a normal diet.