Post-transplant lymphoproliferative disease (PTLD) is a well-recognized complication of the intense immunosuppression required in solid organ and bone marrow transplant recipients. The clinical presentation is varied and can range from a benign infectious mononucleosis-like syndrome to malignant lymphoma. PTLD manifesting as multiple myeloma occurs rarely. We report the unique occurrence of Epstein–Barr virus (EBV)-associated post-transplant multiple myeloma in a 16-year-old male. In contrast to previously described cases of PTLD-myeloma type, this patient was very young, had a clear association with EBV, and an indolent clinical course. © 2005 Wiley-Liss, Inc.