Three young adult patients are described to illustrate an uncommon syndrome, papillophlebitis. This entity, characterized by mild but protracted monocular visual impairment, edema of the optic disc, retinal venous engorgement, and perivenous retinal hemorrhages, resembles atherosclerotic occlusion of the central retinal vein in older patients. In younger individuals it is benign and self limited, but may be incorrectly diagnosed as optic neuritis or papilledema. These alternatives can usually be excluded if tests of visual function do not indicate an optic nerve conduction defect and if the clinical presentation and examination of the opposite ocular fundus do not disclose evidence of increased intracranial pressure. Because resolution usually occurs spontaneously, immediate neuroroentgenographic tests may be inappropriate. Effective treatment has not been established; local instillation of corticosteroids may hasten recovery.