Goals: The aim of this study was to compare the esophageal contractions in Chagas‘disease and in idiopathic achalasia. Background: It is suggested that the esophageal involvement caused by Chagas‘disease and by idiopathic achalasia,although similar, shows some differences. Study: We studied the contractions at 2, 7 , 12, and 17 cm below the upper esophageal sphincter in 25 patients with idiopat hic achalasia (15 with dilatation), 52 with Chagas‘disease (22 with dilatation) , and 18 controls. Each subject performed 5 swallows of a 5 mL bolus of water al ternated with 5 dry swallows. Results: In the distal esophageal body, the amplit ude was lower in patients than in controls. Among patients with esophageal dilat ation, the proximal amplitude was lower in patients with idiopathic achalasia, a nd the time interval between the contractions at 2 and 7 cm was longer in patien ts with Chagas‘disease, the number of failed contractions was higher in Chagas ‘disease, and simultaneous contractions were more frequent in idiopathic achala sia. The simultaneous isobaric pressure in the distal esophagus was associated w ith an increase in proximal pressure that was higher than distal but lower than proximal swallowing pressure. Conclusion: The results suggested that idiopathic achalasia and Chagas‘disease cause similar impairment of distal esophageal moti lity, but in patients with esophageal dilatation the impairment of proximal moti lity may be not the same. Goals: The aim of this study was to compare the esophageal contractions in Chagas ’disease and in idiopathic achalasia. Background: It is suggested that the esophageal involvement caused by Chagas’ disease and by idiopathic achalasia, although similar, shows some differences. We studied the contractions at 2, 7, 12, and 17 cm below the upper esophageal sphincter in 25 patients with idiopat hic achalasia (15 with dilatation), 52 with Chagas’ disease (22 with dilatation), and 18 controls. Each subject performed 5 swallows of a 5 mL bolus of water al ternated with 5 dry swallows. Results: In the distal esophageal body, the amplit ude was lower in patients than in controls. Among patients with esophageal dilattion, the proximal amplitude was lower in patients with idiopathic achalasia, a nd the time interval between the contractions at 2 and 7 cm was longer in patien ts with Chagas ’disease, the number of failed contractions was higher in Chagas’ disease, and simultaneous c ontractions were more frequent in idiopathic achala sia. The simultaneous isobaric pressure in the distal esophagus was associated w ith an increase in proximal pressure that was higher than distal but lower than proximal swallowing pressure. Conclusion: The results suggested that idiopathic achalasia and Chagas’disease cause similar impairment of distal esophageal moti lity, but in patients with esophageal dilatation the impairment of proximal moti lity may be not the same.