Fifty-seven cardiac transplants in 53 patients have been performed; 30 survived for at least three months. Malignant neoplasms developed in three (10%) of these patients. This incidence is more than double that in recipients of donor kidneys at our institution. Kaposi's sarcoma developed in three patients in the combined groups and accounted for 30% of all malignant neoplasms. The possible reasons for these high incidences are discussed. © 1983, American Medical Association. All rights reserved.