Immunosuppressive therapies may induce neoplasia. The administration of cyclosporine is associated with an increased frequency of lymphoproliferative disorders when compared with conventional therapies. This risk is related to the type of organ transplanted and immunosuppression modalities (type and intensity). In heart transplantation, the incidence of non-Hodgkin's lymphoma varies between 11.9 and 1.5% with onset usually about 6 months after transplantation. Four case reports are presented; 3 lymphomas and 1 multiple myeloma that developed, in heart transplant recipients receiving triple-drug immunosuppression: azathioprine, cyclosporine and prednisolone. Clinical and immunohistological characteristics of posttransplant lymphomas are described and etiopathological mechanisms, especially the role of cyclosporine, in the development of these lymphoproliferative disorders, are discussed.