AIM: To evaluate the peroxynitrite (ONOO-) of puerarin on retinal pigment epithelial (RPE) cells apoptosis induced partly by peroxynitrite via Fas/FasL. METHODS: RPE cells from C57BL/6 mice eyes were cultured. Diabetes was induced in Sprague-Dawley (SD) rats by streptozotocin (STZ) intraperitoneal injection. Puerarin was administrated to cultured RPE cells and diabetic rats. Western blotting analysis, DNA ladder, RT-PCR, immunohistochemistry were used for determining the expression of nitrotyrosine (NT, the foot print of ONOO-), complement 3 (C3); apoptosis and inducible nitric oxide synthase (iNOS) mRNA as well as Fas/FasL signal transduction in RPE cells. RESULTS: Both RPE cells in ONOO- and puerarin group developed apoptosis and expressed NT, C3, iNOS mRNA and Fas/FasL. But latter delayed the all changes in a time-dependent manner compared with control and STZ group (P＜0.001). iNOS, C3 and Fas/FasL were up-regulated and associated with an increase of expression of ONOO- in vivo and in vitro. CONCLUSION: Puerarin decreases RPE cells apoptosis partly induced by ONOO- for diabetic retinopathy.