Development of secondary malignancies is a well-known complication of solid organ transplant, with skin cancer and lymphoproliferative disorders being most frequently observed. Posttransplant lymphoproliferative disorders, caused by diminished immune surveillance, represent a broad spectrum of pathological and clinical disorders, ranging from benign conditions to very aggressive lymphomas. Here we review treatment options for adult patients experiencing posttransplant lymphoproliferative disorders following solid organ transplant.