The cases of 23 patients with unilateral combined central retinal artery-central retinal vein obstruction are described. Criteria for the abnormality included: a history of relatively sudden visual loss; superficial retinal whitening in the posterior pole in combination with a cherry spot; and intraretinal blood, generally associated with dilated and/or tortuous retinal veins. In five instances (22%) the obstructions developed after retrobulbar injection. Among the 21 patients with followup for at least 6 months, or until the onset of neovascularization of the iris, 17 (81%) developed rubeosis iridis. Late histopathology was obtained in two eyes. Hemorrhagic necrosis of the retina was observed in some areas of the posterior pole and attenuation of the inner retinal layers, similar to that seen with late central retinal artery obstruction, was noted elsewhere. Periphlebitis of the central retinal vein within the optic nerve was found in each case.