Using the TUNEL method, we examined the effect of intraocular NT-4/5 injections on cell death in ganglion and non-ganglion cell layers in 5-day-old rat retinas. NT-4/5 reduced the level of naturally occurring cell death in all retinal layers. Twenty-four hours after superior colliculus (SC) lesions there was a significant increase in the density of TUNEL+ profiles in the RGC layer (6.43/mm2 in normal vs (8.89/mm2 after lesions) which was ameliorated by intraocular NT-4/5 injections (8.79/mm2). Surprisingly, after SC ablation a significant increase in TUNEL+ profiles was also seen in non-ganglion cell layers (52.25/mm2 in normal vs 89.35/mm2 after lesions), mostly in the developing inner nuclear layer. Death in non-ganglion cell layers was also significantly reduced (43.09/mm2) after NT-4/5 eye injections.