Since 1976, the procedure of choice for patients with Marfan aneurysm of the ascending aorta at this institution has been the Bentall procedure or its modification. One hundred seventy-four Marfan patients have had ascending aortic aneurysm repair with a prosthetic composite graft. An additional four children and two adults have had aortic root replacement with a cryopreserved homograft. Thirty-seven (21%) patients came to operation with an acute or chronic dissection involving the ascending aorta. Thirty-one (17%) patients having aortic root replacement also had mitral valve repair or replacement. The first 86 patients in the series had a hemostatic Bentall wrap constructed; however, in the last 88 patients, the ascending aorta has been transected completely and the aortic wall tacked loosely over the composite graft. It is our preference to construct a direct end-to-side anastomosis of each coronary ostium to the side of the composite graft. In the past, we used the Cabrol interposed graft for low-lying coronary ostia, but currently favor the "button technique" for this procedure. One hundred fifty-six of 180 patients underwent elective root replacement with no hospital mortality. Twenty-four patients underwent urgent or emergency surgery; 17 of these patients with acute dissection or rupture underwent emergency surgery. Two of these patients with rupture died intraoperatively. Therefore, overall hospital mortality among the 180 patients was 1.1%. There have been 14 late deaths among 178 patients discharged from the hospital (7.9%). Five of these late deaths occurred among our first 11 patients operated on between 1976 and 1979. Since 1980, there have been nine late deaths among 167 patients (5.4%).(ABSTRACT TRUNCATED AT 250 WORDS)