Programmed cell death is an important process in normal embryonic development, adult tissue maintenance, maintaining animal homeostasis by controlling cell numbers, removing abnormal cells, and sculpting developmental structures in normal morphogenesis. DNA fragmentation, carried out by DNase activity, is one of the important events during morphogenesis of insect development. In this study, DNase activities of holometabolic Ephestia kuehniella Zeller (Lepidoptera: Pyralidae) were evaluated during its life stages. The tissues of E. kuehniella degenerate during larval-pupal metamorphosis. The DNase activities for the 27 day old larvae, 1 day old pupae and adult (youngest individuals) were found to be 0.270, 0.428, and 0.310 kunitz unit (Ku), respectively. The DNase activities of larvae, pupae and adult were found to be 0.376, 0.759 and 0.436 Ku for middle; and 0.522, 1.535 and 1.156 Ku for the oldest age groups, respectively. There was increasing DNase activity of larvae depending on the ages. Age dependent increase in DNase activity was also observed for pupae and adults. Our findings indicated that DNase activity is the leading force for programmed cell death during metamorphosis. When different developmental stages were considered, the highest DNase activity was observed in pupae and the lowest in the larvae.