The SpltNPV DNA can induce the apoptosis of SL-1 was discovered. Microscopic examination of Spodoptera litura (SL-1) cell transfected with DNA of Spodoptera litura nucleopolyhedrovirus revealed progressive cell blebbing starting at 6 h postinfection and culminating in total cell destruction at 18 h postinfection. The fragmentation of the infected cell nuclei and apoptotic body were observed by stained with the specific fluorescent dye DAPI. Agarose gel electrophoresis analysis of the DNA extracted from infected cells showed typical DNA ladder. All these supported that the transfected SL-1 cells undergo apoptosis. Neither apoptosis nor polyhedra was observed in the SL-1 infected with the virions of SpltNPV.