Apoptosis signal-regulating kinase 1(ASK 1) is one of a growing number of mitogen-activated protein kinase (MAPK) kinase kinases identified in the c-Jun N-terminal kinase and p38 MAPK pathways. ASK 1 mediates diverse biological signals leading to cell death, differentiation, survival, and senescence, in response to cellular stress and the innate immune response. In the retina, ASK 1 is mainly expressed in retinal ganglion cells, and loss of ASK 1 leads to mild damage after ischemic injury. Consistently, ASK 1 deficient retinal ganglion cells were resistant to hydrogen peroxide. Our findings suggest that ASK 1 is involved in retinal cell death due to oxidative stress and may be a new therapeutic target for retinal degeneration.