Graves' ophthalmopathy (GO) is one of the frequent manifestations of the disorder which is an inflammatory process due to fibroblast infiltration, fibroblast proliferation and accumulation of glycosaminoglycans. Eye irritation, dryness, excessive tearing, visual blurring, diplopia, pain, visual loss, retroorbital discomfort are the symptoms and they can mimic carotid cavernous fistulas. Carotid cavernous fistulas are abnormal communications between the carotid arterial system and the cavernous sinus. The clinical manifestations of GO can mimic the signs of carotid cavernous fistulas. Carotid cavernous fistulas should be considered in the differential diagnosis of the GO patients especially who are not responding to the standard treatment and when there is a unilateral or asymmetric eye involvement. Here we report the second case report with concurrent occurrence of GO and carotid cavernous fistula in the literature.