AIM: To investigate the relationship between retinal degeneration caused by high-fat diet induced obesity and oxidative stress in C57BL/6 mice·METHODS: Mice were fed a high-fat diet for 19 weeks and then divided into diet induced obesity-resistant(DIO-R) group and diet induced obesity(DIO) group,control group mice were fed a basal diet at the same time.The retinal ultrostructural changes were detected by light and transmission electron microscope.The cellular apoptosis was detected by TUNEL.Oxidative indices were detected by biochemical methods·RESULTS: The retinal and ONL thicknesses in DIO group were thinner than in control and DIO-R groups(P<0.01).The photoreceptors in DIO group showed characteristic features of apoptosis and necrosis;the photoreceptor disk membranes were disordered and some of them were dissolved and fractured;the retinal ganglion cell in DIO group showed smaller and condensation of nuclear chromatin and increased electron density of the cytoplasm.TUNEL staining showed apoptosis cells in ONL in DIO group increased and the percentage of apoptotic cells was much higher than in control and DIO-R groups(P<0.01).Compared with the control group,the level of malondialdehyde(MDA) increased(P<0.01) and the activity of superoxide dismutase(SOD) decreased significantly(P<0.05) in DIO group·CONCLUSION: High-fat diet induced obesity may cause retinal degeneration and cellular apotosis in C57BL/6 mice,which may be related with oxidative stress in some extent.