In this study, we investigated whether or not lymphokine-activated killer (LAK) cells can damage renal tissue and therefore whether they may contribute to graft destruction during kidney allograft rejection. Human peripheral blood mononuclear cells were activated with a lymphokine preparation and the resulting LAK cells were tested against kidney cells from various sources. Renal cancer cells as well as cultured normal kidney cells were efficiently lysed by LAK cells, as assessed with Cr-labelled target cells, showing that both cell types are sensitive to LAK cell-mediated cytolysis.