Post-transplant lymphoproliferative disorder (PTLD) represents a spectrum of lymphoid proliferative diseases seen as result of immunosuppression in recipients of solid organ or hematopoietic stem-cell transplantation. Options of treatment include reduction or discontinuation of immunosuppressive agents, antiviral drugs, rituximab, chemotherapy, and radiation. We report two unique cases of PTLD (CNS and plasmacytoma-like) treated successfully with salvage chemotherapy, mini-BEAM chemotherapy, and autologous stem-cell transplant. In both cases, patients were also treated with sirolimus and prednisone as immunosuppression, and neither patient rejected their solid organ transplants. With over 30 months of follow-up, both patients remain in complete remission with excellent allograft function.