Nonablative hematopoietic cell transplantation (HCT) is becoming a preferred treatment for those recipients in whom the potential toxicity risk of standard ablative allogeneic therapy may be unacceptable. Graft-versus-malignancy effects may be generated against epithelial malignancies which are similar to the graft-versus-leukemia activity that is well documented in human hematological malignancies. Renal cell carcinoma has been shown to be responsive to immunotherapy with recombinant human cytokines and may be an ideal model for exploring this novel therapy. Clinical investigations have demonstrated regression of metastatic renal cell carcinoma occurs in some patients following nonablative allogeneic HCT. However, graft-versus-host disease remains a significant toxicity of nonablative transplantation, and further investigations are warranted to further evaluate this promising approach and to improve its safety.