Abstract: AIM: The effect of dl-3-n-butylphthalide on cerebrocortical neuronal apoptosis induced by hypoxia/hypoglycemia was investigated. METHODS: The DNA content and percentage of apoptosis were measured by flow cytometry; Morphological changes were observed with light microscope and electron microscopy; DNA fragmentation was analyzed by agarose gel electrophoresis and terminal dUTP nick-end-labeling(TUNEL) method. RESULTS: The result showed that hypoxia/hypoglycemia(12 h) and reoxygenation(12 h) medium induced apoptosis in primary cultured cortical neurons. dl-3-n-Butylphthalide(10 μmol.L^-1) was found to decrease the percentage of neuronal apoptosis, prevent DNA fragmentation, ameliorate morphological changes of cortical neurons and reduce the numbers of positive cells. CONCLUSION: These findings indicate that dl-3-n-butylphthalide prevented hypoxia/hypoglycemia-induced apoptosis of rat cortical neurons. These results further revealed the mechanisms of dl-NBP in reducing the volume of the cerebral infarct after middle cerebral artery occlusion in rats.