After implanting 19mm and 21mm Sorin pericardial aortic valves (AVR) in 35 women over the age of 60 years, it was our clinical impression that these patients had an unduly high incidence of residual valve stenosis. A retrospective comparison of our experience with this valve and the 19mm St. Jude mechanical AVR in a similar group of 26 patients, operated during the same period (October 1987 to July 1994), was carried out. In comparison to the 19mm St. Jude valve, the 19 mm Sorin Pericardial valve was associated with significant residual stenosis in elderly women despite similar body surface areas. This prosthesis/patient mismatch was not eliminated by the use of a 21 mm Sorin pericardial valve. Although the Sorin pericardial valves was associated with a reduced incidence of thromboembolism and anticoagulation related hemorrhage, it had a significantly increased risk of permanent valve related morbidity and mortality. As a result if this experience we have discontinued our use of the Sorin pericardial valve.