Aprotinin has been used in pediatric cardiac surgery for its antiinflammatory and hemostatic benefits. We have reported that aprotinin has a direct cellular neuroprotective effect through reduction of excitotoxicity. The purpose of this study was to investigate whether aprotinin is neuroprotective against apoptotic cell death. Near-pure neuronal cultures containing <5% astrocytes were obtained from fetal mice. Serum deprivation was initiated at 7 days by transferring the cultures, which are dependent on serum for survival, into growth medium lacking serum for 24 h. Neuronal cell death was assessed by phase-contrast cell counting after staining with 0.4% trypan blue dye. Aprotinin at a clinically relevant concentration of 100 KIU.mL(-1) significantly reduced apoptotic neuronal cell death from 84.4% to 51.8%. This result suggests that aprotinin has the potential to reduce brain injury resulting from apoptotic cell death induced by an ischemic insult. Additional studies are needed to evaluate the potential of aprotinin to reduce neurological injury in patients at high risk of cerebral injury, including those undergoing circulatory arrest.