The data were reviewed of 42 patients who had valvulotomy for severe aortic valve stenosis before 1968. All were over age 2 years (mean age 11.3 years). The mean time of follow-up after surgery was 10.6 years (range 6 to 16.3 years). No patient died at operation. Two late deaths were from endocarditis with aortic regurgitation, and one patient with severe arotic regurgitation died suddenly; three patients had valve replacement for aortic regurgitation and one required repeat valvulotomy. Five patients could not be traced. Major symptoms were alleviated in all patients. Left ventricular pressures were obtained in 15 patients before and after operation; the mean gradient averaged 100 mm Hg before and 43 mm Hg after operation. No patient had significant aortic regurgitation before operation. Twelve had moderate to severe regurgitation after operation. The incidence of late valve calcification at a mean time of 10.6 years after operation was small, and restenosis was uncommon. Because moderate or severe incompetence can be produced and stenosis is often incompletely relieved, the operation is palliative, but the low morbidity and mortality rates suggest that it is an effective procedure if stenosis is severe and life-threatening.