The effect of general anesthetics on the developing brain is receiving growing attention. Nonetheless, there remains a paucity of evidence regarding the effect of sevoflurane, a widely used anesthetic in pediatric anesthesia. This study was designed to investigate the effect of sevoflurane on nerve cell apoptosis in the developing brain. Techniques to detect cell apoptosis included immunohistochemistry of cleaved caspase-3 and single-strand DNA, as well as electron microscopy. Elevated cleaved caspase-3 was also validated semi-quantitatively by immunoblotting assay. Mouse pups (day 7 postnatal) were subjected to sevoflurane inhalation. Twelve hours later, dramatically increased cleaved caspase-3 and single-strand DNA immunoreactivity were detected in the pup brains. Immunoblotting assay of cleaved caspase-3 revealed a significant increase after anesthetic exposure. Electron microscopy disclosed typical apoptotic morphology of the degenerative nerve cells. Blood glucose levels in the anesthetized group were not different from those of the control group, indicating that the neuronal apoptosis observed in the anesthetized group was not the result of hypoglycemia. Our results indicate that subanesthetic concentration of sevoflurane can trigger neuronal apoptosis in the postnatal mouse brain.