The retinal toxicity of intravitreally injected steroids, fluorometholone and tetrahydrocortisol, was examined. The concentration of the steroids was 20 mg/ml, and 0.05 ml of each solution were injected into the rabbit vitreous cavity. An equal volume of saline solution was injected as a control. In addition to ophthalmoscopy, intraocular pressure was measured and electroretinography, light microscopy and electron microscopy were performed. The results showed no remarkable changes in all eyes. Fluorometholone and tetrahydrocortisol seem to have neither toxicity to the retina nor adverse effect of elevating intraocular pressure when intravitreally injected with this amount.