From January, 1975, to December, 1980, 83 patients with sliding hiatal hernia, gastroesophageal reflux, or both were treated using a modified Collis gastroplasty associated with either partial or total gastric application. When partial plication was used, the five-year clinical results were considered satisfactory in 27 out of 35 patients (77%). When total plication was used, the results were satisfactory in 41 out of 46 patients (89%) after follow-up ranging from 12 to 60 months (average, 36 months), but no symptoms of gastroesophageal reflux reappeared in any patient. In patients undergoing partial plication, the mean preoperative high-pressure zone of 11.20 +/- 8.19 mm Hg increased after operation to 17.31 +/- 10.50 mm Hg, but in the second postoperative studies the value decreased to 13.69 +/- 7.24 mm Hg. When 360 degrees plication was used, the preoperative value of the high-pressure zone--9.36 +/- 4.80 mm Hg--increased after operation to 17.70 +/- 7.53 mm Hg but did not decrease significantly in the second postoperative studies: 16.46 +/- 7.99 mm Hg. When partial plication was used, the positivity of the abdominal compression test was 9 and 28% in the early and late postoperative studies, respectively. Using total plication, the percentage of positivity in the early and late postoperative periods was 0 and 2%, respectively. Concerning the acid reflux test, when partial plication was used, the test was positive in 3 out of 27 patients (11%) in the early postoperative studies and in 7 out of 30 (23%) one year later. For the total plication procedure, the percentage of positive tests was null in the first control and 3% in the second postoperative studies.