The CryoLife-O'Brien stentless valve is a composite trileaflet porcine aortic valve. It is assembled from 3 non-coronary leaflets and has no foreign material support. It is therefore truly stentless. From December 1992 to January 1996, 118 patients with aortic valve replacement had a CryoLife-O'Brien stentless valve inserted at the Prince Charles Hospital, Brisbane. The mean age was 73 years (range 59-89) and 54% were men. Most patients had aortic stenosis secondary to a calcific degenerative valve. Follow-up is 100% with hematological and echocardiographic studies before discharge, at 6 months, and at 12-18 months. Five deaths (2 early and 3 late) have occurred and morbidity includes 3 strokes, 1 peripheral embolism, 3 perivalvular leaks, and 1 patient with late endocarditis. Valve performance has been good, with low transvalvular gradients and only a trace or no regurgitation in over 95% of patients after 18 months. No structural deterioration or hemolysis has occurred. Echocardiographic surveillance confirms a very effective central orifice. Short-term results show that the overall performance of the CryoLife-O'Brien stentless valve has been very satisfactory, with low mortality and morbidity in this elderly group of patients. The benefits include the absence of prosthetic material, wide leaflet coaptation, and a quick and easy insertion. Long-term anticoagulation is not necessary. It is particularly suitable for elderly patients with a symmetrical aortic root.