A 16 year-old male with B-cell non-Hodgkin's lymphoma presenting as a cardiac tumor and superior vena caval (SVC) syndrome received a haploidentical stem cell transplant (SCT) from his mother after conventional and salvage chemotherapy. He received additional radiation therapy for the residual tumor and is alive and well on day 640 after transplantation. Malignant lymphoma presenting as a cardiac tumor, including primary cardiac lymphoma, is rare. Although many reports have shown the poor prognosis of cardiac lymphoma, our case suggests that allogeneic haploidentical SCT might be useful for the treatment of aggressive cardiac lymphoma.