Enlargement of the ascending aorta may coexist with concomitant valvular, coronary, or other cardiac diseases. If dilation is moderate (i.e., <6 cm diameter) and another cardiac procedure is being performed, we have reduced the diameter of the ascending aorta with an S-shaped incision and excision of the curves of the "S" as a modified Z-plasty. We have performed the procedure in 23 patients with concomitant procedures including aortic valve replacement in 21 (1 as a pulmonary autograft), coronary bypass in 1, and resection of subaortic stenosis in 1. There were 15 males and 8 females with a mean age of 53 years (range 8-67 years). The mean maximal preoperative diameter on transesophageal echocardiography was 5.0+/-0.7 cm (range 3.2-6.6 cm). The mean intraoperative postreduction diameter was 3.1+/-0.6 cm (range 2.1-4.1) (p<0.01). All patients tolerated their procedures well. Sixteen patients were studied by transthoracic echocardiography postoperatively. These patients had a mean intraoperative postreduction diameter of 2.9+/-0.65 cm that increased to 3.1+/-0.45 cm (p = NS) after a mean follow-up of 9.9+/-12.6 months. Of these, seven patients were studied >1 year postoperatively. Their mean intraoperative postreduction diameter of 2.9+/-0.5 cm increased to 3.1+/-0.35 cm (p = NS) after a mean follow-up of 22.1+/-9.2 months. No known recurrences of the aneurysms have occurred. We feel this technique is valid in patients with moderate aortic dilation undergoing concomitant cardiac procedures and in whom more aggressive aortic interventions are not warranted.