Bilateral cases of branch retinal vein occlusions (BRVO) are infrequent and often related to systemic disease. A 72-year-old man with biochemical recurrence of prostate cancer was referred for decreased vision in his left eye. Fundus examination and fluorescein angiography disclosed bilateral BRVO with patches of peripheral non-perfusion and macular oedema in the left eye. A systemic work up revealed elevated fibrinogen and reduced free protein S antigen, consistent with an underlying hypercoagulable state. Cancer is a well-known cause of hypercoagulability. We report the first case of bilateral BRVO related to biochemical recurrence of prostate cancer and a proven coagulation derangement.