Essential thrombocytosis (ET) is an uncommon myeloproliferative disease characterized by overproduction of platelets that may cause bleeding and thrombosis or may be asymptomatic as well. Other myeloproliferative disorders and myelodisplastic syndrome must be ruled out for ET diagnosis. In this study, we evaluated the ophthalmoscopic, optic coherence tomography and angiographic evidence of branch retinal vein occlusion in a 41 years old man with essential thrombocytosis who complained about acute visual loss of the right eye. Ophthalmic examination, including visual acuity, intraocular pressure, anterior and posterior segment examination, fluorescein fundus angiogram and optic coherence tomography (OCT) were performed in our clinic. We diagnosed superotempoal branch retinal vein occlusion (BRVO) in the right eye and we applied intravitreal anti-VEGF (vascular endothelial growth factor) ranibizumab (Lucentis®, Novartis) and sector scatter retinal argon laser photocoagulation subsequently. Left eye examination was normal. We suggested that thrombocytosis and other thrombophilic factors should be considered as one of the causative factors in atypical cases with BRVO, though the effect of thrombophilic factors in etiology of the BRVO is controversial