Oxidative injury is believed to be a major factor in the pathogenesis of a variety of neurodegenerative diseases. Additionally, the mode of cell death in oxidant-stressed cells can vary. The present study was conducted to evaluate the use of a primary neuronal cell-based bioassay in which different modes of oxidant-induced cell death could be studied and in which putative neuroprotective agents could be screened. Addition of 50 μM H 2 O 2 to primary cortical neuronal cultures for 1 h under normal ATP conditions resulted in approximately 40% cell death, almost exclusively of an apoptotic nature. In this condition, cell death was effectively blocked by GM1 ganglioside, the semi-synthetic ganglioside derivative LIGA20, the dopamine receptor agonist pramipexole (PPX) and the caspase inhibitor Z-VAD-FMK but not by the poly (ADP-ribose) polymerase (PARP) inhibitor 3-aminobenzamide (3-AB). Pretreatment of cells with 0.01 μM oligomycin for 45 min prior to addition of 50 μM H 2 O 2 caused significant ATP depletion and approximately the same amount of cell death as H 2 O 2 alone. However, under these conditions, cell death was primarily non-apoptotic in nature and GM1, LIGA20 and Z-VAD-FMK had no protective effects. In contrast, AB and PPX effectively blocked cell death. These results suggest that cellular ATP plays a critical role in determining the mode of cell death in primary neurons and that these types of in vitro models may provide a useful system for screening putative neuroprotective agents.