We examined nine patients who presented cilioretinal artery occlusion (CLRAO) associated with retinal vein occlusion (RVO). CLRAO was probably secondary to the raised intraluminal resistance consequent to the RVO in patients showing initially a delayed filling of the cilioretinal artery in fluorescein angiography. Interestingly, these patients presented an ophthalmoscopically more severe form of RVO and had systemic predisposing factors for a RVO. In patients presenting a physiological perfusion of the cilioretinal artery in fluorescein angiography, RVO was a self limited disease and etiologic factors were not found. This may suggest that in these patients the CLRAO probably occurred simultaneously with the RVO after a decrease in perfusion pressure in both retinal and cilioretinal arterial systems. In this combined vaso-occlusive retinopathy the vulnerability of cilioretinal arteries can be explained either by the absence of autoregulation or by their lower perfusion pressure gradient in comparison with retinal arteries.