A series of 13 patients (11 male, 2 female, average age 61 +/- 6 years) with previous aortocoronary bypass surgery and reoperated for aortic valve replacement (AVR) were analysed retrospectively. At coronary bypass, 8 patients (Group I) has insignificant aortic stenosis (AS) (mean transvalvular pressure gradient < 40 mmHg and/or aortic valve surface > 1 cm2). The other 5 had no aortic valvular lesion (Group II). The average time interval between the two operations was 7 +/- 3.3 years (Group I: 6.7 +/- 3.5 years; Group II: 7.4 +/- 3.2 years). In Group I, 2 patients required early AVR (2 years) whereas the time of reoperation varied from 6 to 12 years in the other 6 patients. No operative complications related to the sternotomy or dissection of adhesions were observed. In 3 cases, it was necessary to free the implanted grafts on the right coronary artery to gain access to the initial part of the aorta. A transverse low aortotomy allowed AVR in good conditions in all cases. One patient in Group II died on the 5th postoperative day of a low output syndrome complicated by pneumonia. After an average follow-up of 3 +/- 2 years, 9 patients are still alive. Three patients in Group I died, two of cardiac failure and one of unknown causes. The authors conclude that "prophylactic" AVR in cases of insignificant AS in patients referred for coronary bypass surgery is not justified. Regular echocardiographic follow-up should lead to AVR at the most appropriate moment, sometimes after an interval of several years, with a low operative risk.