Apoptosis induced by H-1 parvovirus infection was investigated in C6 rat glioblastoma cells and in newborn rats. Apoptotic changes, such as chromatin condensation, the appearance of apoptotic nuclear bodies and oligonucleosomal DNA ladders, were observed in infected C6 cells 2 days after infection. Inhibitor assay results suggest that a caspase-3-dependent apoptosis activation pathway is induced by H-1 virus infection in C6 cells. Observations made in vivo revealed that the number of apoptotic cells increased in the infected cerebellum, coinciding with known virus infection sites.