We repaired coarctation of the aorta in a group of 18 children less than 3 years old, using either resection with end-to-end anastomosis (8 patients, Group 1) or patch graft aortoplasty (10 patients, Group 2). The two groups were similar preoperatively in age, pressure difference between proximal and distal aorta (delta PA0), and severity of aortic arch hypoplasia. Three patients, all less than 2 months old, died early postoperatively. Among the survivors, the right brachial artery systolic pressure was significantly higher in Group 1 (133.1 +/- 7.0 mm Hg) (mean +/- standard error of the mean) than in Group 2 (102.5 +/- 7.2 mm Hg) (p less than 0.05). The delta PA0 was significantly higher in Group 1 (33.0 +/- 7.5 mm Hg) than in Group 2 (5.1 +/- 2.3 mm Hg) (p less than 0.01). Three patients in Group 1 required reoperation and were treated with patch graft aortoplasty; relief of delta PO0 was complete in 2. Patch graft aortoplasty is more effective than resection in reducing proximal aortic systolic pressure and in relieving delta PA0 in infants and small children with coarctation of the aorta.