The pathogenesis of immunological and nonimmunological components that cause chronic kidney allograft nephropathy (CAN), is not yet completely understood. To explore the possible contribution of alloreactive cytotoxic T cells, we analyzed the transcription of cytotoxic molecules such as granzyme B and perforin using semiquantitative RT-PCR on surgically removed grafts obtained from two groups: group 1 (n = 10) were cases of CAN; group 2 (n = 3) had no CAN. Among group 1 kidneys, granzyme-B was expressed in 7 of 10, whereas perforin was detectable in 9 of 10 cases; their detection was not related to the presence of superimposed signs of acute graft lesions. Cytotoxic molecules were never found in group 2 kidneys. These results show that explanted chronically rejected grafts display cytotoxic molecule transcripts in addition to Th2 type cytokines, such as IL-10, IL-3, and IL-6, suggesting that both cellular and humoral alloreactive mechanisms may play important roles in CAN pathogenesis.