Between 1979 and 1988, 60 patients with achalasia were treated by pneumatic dilatation under general anaesthesia, using the Rider-Moeller apparatus. The diagnosis rested on clinical, radiological, manometric and endoscopic criteria. These 60 patients underwent a total of 99 dilatations: 63.3 per cent were dilated once and 37.7 per cent were dilated several times. Forty seven of the 60 patients were followed up for more than 12 months (mean: 44 months): 2 of them (4.2 per cent) had to be operated upon, while 45 (95.7 per cent) are asymptomatic. Immediate complications were perforation in one case and cardial fissure in another; both were treated medically and cured. There was no oesophagitis or peptic stenosis, and no patient died. These results are compared with those found in the literature. The authors underline the simplicity, safety and effectiveness of pneumatic dilatation and suggest that it should be used as first-line treatment of achalasia, surgery being performed only when dilatation fails.