Between April 1969 and November 1973 103 patients underwent isolated mitral replacement with three-cusp stented tissue valves. Autologous fascia lata was used in 50 patients, homologous fascia lata in 21, and heterologous pericardium in 32. The early mortality rate (14.6%) was influenced by age, the extent of preoperative cardiac disability, and low cardiac output. The survivors were followed up for periods varying from 8 to 60 months (average 37 months). In general, a factor in late death (13.6%) was high preoperative pulmonary artery pressure. In the autologous fascial series valve failure and infective endocarditis were significantly related to late mortality. The results with homologous fascia and pericardium were better than with autologous fascia valves. The incidence of postoperative mitral regurgitation was singificantly lower in the homologous fascial and pericardial series and none of these grafts had to be removed. The incidence of thromboembolism was low without anticoagulants. Actuarial analysis showed a survival rate at five years of 82.2 per cent. We no longer use autologous fascial valves. Though better results have been obtained with both homologous fascia and pericardium we prefer the physical characteristics of heterologous pericardium and it is easy to obtain.