The Authors explain the experience about the porcine xenograft, the results of the application of 98 bio-prostheses implanted between January 1976 and November 1979. The distribution of the implantations is: 52 mitral valve reimplantation; 16 aortic valve reimplantation, 2 tricuspid valve reimplantation, 26 xenograft were implanted with the association of another prosthesis or aorto coronary by-pass graft. The patients were selected for clinical criteria (age, sex, geographic provenance) and haemodinamic criteria. Three early embolism were checked, one lethal. The total mortality is of 9 patients: 4 patients were submitted to multiple surgical operation. The running of porcine xenograft is good on the middle term.