We presented three cases with refractory metastatic renal cell carcinomas who underwent nonmyeloablative allogeneic peripheral blood stem cell transplantation(PBSCT). A fludarabine and cyclophosphamide-based regimen was used. Complete donor-T-cell chimerism was established at day 94, 40, 52 after PBSCT in each case. GVHD occurred at day 183, 53, 75. In Case 1 and Case 3 apparent GVT effects reduced the metastases at day 212, 261 and let them live longer than expected. Case 2 died at day 69 before GVT effect appeared, because the case was so-called rapid growth type. Histological examinations in Case 1 and Case 3 showed infiltration of lymphocytes disrupting the foci of renal cell carcinomas which was considered as findings of GVT effects.