Granulocyte colony-stimulating factor (G-CSF) protects neurons against experimental focal cerebral ischemia. However, its neuroprotective effect on human brain is unknown. We sought to determine whether G-CSF can protect the human cerebral neurons in vitro. Human cerebral-neuroblastoma hybrid cell line (A1) was exposed to oxygen and glucose deprivation with or without G-CSF. G-CSF promoted cell survival and decreased cytotoxicity effectively at 25 ng/ml. G-CSF reduced early apoptotic (annexin V+/PI-), and late apoptotic or necrotic (annexin V+/PI+) cells, and decreased active caspase-3 immunoreactivity. G-CSF could protect human cerebral neurons following in vitro ischemia.