Post-transplant lymphoproliferative disorder (PTLD) is a frequent and often fatal complication of organ transplantation. It most often results from an Epstein-Barr virus (EBV)-transformed B-cell clone, which expresses B-cell surface markers such as CD20. We describe a case of a heart transplant recipient who EBV seroconverted post-transplant and subsequently developed subcutaneous and lymphatic B-cell lymphoma, successfully treated with CD20 antibody (rituximab). The patient has been in remission during 10 months of clinical follow-up. Copyright © 2001 International Society for Heart and Lung Transplantation.