Cutaneous T-cell lymphomas are a type of indolent non-Hodgkin's lymphoma where patients with limited skin disease can be successfully treated with a variety of skin-directed, systemic, and immunomodulating therapies, whereas durable remissions are difficult to achieve in patients with tumor, erythrodermic, or systemic disease. We describe a patient with cutaneous T-cell lymphoma and malignant cells constituting 99% of her peripheral blood lymphocytes who had a sustained complete response after an HLA-matched sibling allogeneic stem cell transplantation. We also review the current literature regarding both autologous and allogeneic stem cell transplantations for advanced stages of cutaneous T-cell lymphoma, discuss the importance of the graft-versus-tumor immunomodulatory effect in successful transplantations, and suggest that allogeneic stem cell transplantation deserves further consideration and study as a potential treatment for selected patients who are younger and at high risk.