We examined whether the nuclear localization of caspase-activated DNase (CAD) are involved in cadmium-induced apoptosis. Exposure of porcine kidney LLC-PK₁ cells to cadmium cleaved poly (ADP-ribose) polymerase (PRAP) as sufficiently as TNF-α did in the renal cells. However, nuclear localization of CAD was not seen during cadmium-induced renal apoptosis, but done during apoptosis by TNF-α. On other hands, in rat splenocytes cadmium could induce nuclear localization of CAD. Thus, our data suggest that activation of caspase is not always to allow the translocation of CAD into the nuclei for the internucleosomal cleavage of DNA, and suggest that the same apoptotic stimulus by cadmium may utilize different sets of caspase cascades or unknown death pathways which are coupled to the caspase proteolysis in different cell types.