Ten patients, all men, have been operated of heterotopic heart transplantation since the end of 1974. Ages ranged from 59 to 24 years with an average of 38 years. Six of them suffered from ischaemic heart disease, two from cardiomiopathy and two from rheumatic heart disease. All of them presented end stage cardiac disease. The first two patients underwent to left ventricular bypass only, in the remaining eight a right and left bypass was performed. At the present time, June 1977, 6 of the original 10 patients are alive all of them in functional class I. Five of them have resumed a full time job, the sixth will be soon able to do so. Four patients died. There were no deaths from acute rejection, but three died from infection, and the fourth one from a pulmonary embolus, 4 months after transplantation. There has been only one episode of acute rejection which has responded well to the treatment. The advantages of the heterotopic versus the orthotopic cardiac transplantation are discussed.