Our goal was to evaluate the DE-T2 biological heart valve prosthesis in our own pulse duplicator system. Pressure drop measurements were made across DE-TP biological aortic valve size 21. All the pulsatile flow experiments were conducted in the Marmara Research Center pulse duplicator system. The pulsatile flow pressures were measured with Motorola MPX5100DP 9306 transducers, interfaced to Vishay 4270A, 4280, 4290, bridge amplifiers and Motorola System 4000. The valve DE-T2 had a vitellium ring with a central bar. The sewing ring was covered with bovine pericardium that continued to form the leaflets. A special incision was made in the pericardium at a 90 degrees angle to the central bar for the formation of two non-anatomical leaflets. The biological aortic valve prosthesis DE-T2 is similar to the natural aortic valve in systolic function. The closing volume is a little higher than the natural valve. Studies are continuing with the aim of diminishing the closing volume and searching for the ideal preservation solution for the pericardium.