The aim of this study is to report the clinical outcome of a diabetic patient with optic nerve head neovascularization treated with an intravitreal injection of triamcinolone acetonide. A 52-year-old patient presented with clinically significant diffuse macular edema and optic nerve head neovascularization due to proliferative diabetic retinopathy in her right eye. Despite grid laser photocoagulation in the macular region macular edema progressed and visual acuity declined. The patient received a single intravitreal injection of 4 mg triamcinolone acetonide with topical anesthesia. After injection of triamcinolone acetonide visual acuity increased and macular edema decreased. Furthermore optic nerve head neovascularization had markedly regressed. No complication was observed during follow-up period. Intravitreal injection of triamcinolone acetonide may be useful for treatment of optic nerve head neovascularization in patients with proliferative diabetic retinopathy.