The Rigiflex achalasia dilator system was used to treat consecutively 24 patients with achalasia. The 30-mm balloon achieved a 70% satisfactory result, and the 35-mm balloon, 93%, including two patients who did not achieve a good response to the smaller balloon. No complications occurred. Dilation pressure, which averaged only 7 +/- 2 (SD) lb/inch2 (psi), was determined by insufflating 1-2 psi more than needed for complete gastroesophageal waist expansion at fluoroscopy. The mean lower esophageal sphincter pressure (LESP) of 39 +/- 11 (SD) mm decreased by 68% with the 35-mm balloon and 60% with the 30-mm. Solid food emptying by radionuclide scintiscan, which pretreatment averaged 62 +/- 36% (mean +/- SD) retention at 20 min, was highly variable both before and in response to dilation. A decrease in scintigraphy of less than 25% retention was present in two of three unsatisfactory treatment responses. A decrease of LESP of greater than 50% and scintigraphy greater than 25% corresponded well with a satisfactory response from the dilation. The excellent results obtained with this system, as well as the distinct advantages of durability, presence of three reliable sizes, and ease of use, make this an attractive alternative to other dilating systems in the treatment of achalasia.