PURPOSE: To investigate the anti-oxidative and anti-inflammatory effects of cilostazol in the ocular tissues of streptozotocin (STZ)-induced diabetic rats. MATERIALS AND METHODS: Diabetes was induced in 6-week-old Wistar rats via peritoneal injections of STZ. The treatment group received cilostazol 18 mg/kg/day for 8 weeks (n = 10), and the diabetic group received phosphate buffer solution (n = 20). The expression of oxidative stress and inflammatory mediators in the ocular tissues was then assessed by reverse-transcription polymerase chain reactions, immunohistochemical (IHC) staining, Western blot analysis, and enzyme-linked immunosorbent assay (ELISA). RESULTS: Reverse-transcription polymerase chain reactions, IHC staining, Western blot analysis, and ELISA showed that cilostazol inhibited mRNA and protein expressions of intercellular adhesion molecule-1, monocyte chemoattractant protein-1 and fractalkine in the retina and aqueous humor (AqH). Consistent with these findings, cilostazol attenuated the activation of nuclear factor-κB (NF-κB) in the diabetic rats. The levels of oxidatively modified DNA (8-OHdG), nitrotyrosine and oxidative lipids (acrolein) were also diminished in the cilostazol-treated group. Chemiluminescence analysis showed that reactive oxygen species (ROS) levels in the AqH was significantly higher in the diabetic rats than in the non-diabetic rats. Treatment with cilostazol significantly reduced the ROS levels in the AqH compared to the diabetic rats. CONCLUSIONS: Our results indicated that cilostazol reduced inflammatory reactions and oxidative stress in diabetic eyes. The anti-inflammatory effects of cilostazol may be indirectly via reducing oxidative stress, inhibiting NF-κB activity, and subsequently decreasing inflammatory mediators. Cilostazol may be beneficial to prevent the progression of diabetic retinopathy.