Abstract: A fixture for testing a circumferentially compliant bioprosthetic valve. The fixture comprises a silicone rubber simulated aorta which approximates the geometry of a healthy human aorta and a cradle for the aorta. The compliance characteristics of the aorta can be selected by varying the proportions of ingredients in the silicone rubber, so that simulated aortas of different compliance but identical geometries can be provided. The compliant valve is disposed inside the aorta and held in place by suturing or the like. In one embodiment, the aorta and valve are supported by means of a cylindrical cradle, with the inflow and outflow ends of the aorta being folded over cylindrical rims on the respective inflow and outflow ends of the cradle. End caps are then fitted in place over the folded-over ends of the aorta, the end caps having holes therein to allow flow through the aorta and valve.