Branch retinal vein occlusion (BRVO) is often associated with arteriosclerosis. Typically the occlusion occurs at an arteriovenous crossing. We report a case of a previously healthy patient who developed a BRVO. Funduscopy and fluorescein angiography suggested an intravascular thrombus as the cause of the occlusion. The investigations performed were positive for systemic hypertension and hyperlipidaemia. After 2 months, fundus examination revealed disappearance of the intravascular thrombus, resolution of the macular edema and improvement of the visual acuity. Certain physiological characteristics of the retinal circulation associated with hyperlipidaemia and systemic hypertension appear to favour thrombus formation.