An unusual case of bilateral blindness secondary to a cavernous sinus thrombosis is reported. A woman who had undergone reconstructive surgery after tumor resection of the floor of the mouth, was readmitted 1 month later with bilateral proptosis and signs of sepsis. There were no complaints of blurred vision. A CT-scan of the orbits demonstrated a bilateral cavernous sinus thrombosis (CST) secondary to an infection at the skull base behind the myocutaneous flap. A few days later she became blind, due to bilateral central retinal artery occlusion and anterior ischemic optic neuropathy. The general critical condition improved with intensive AB treatment. The patient recovered well without neurological defects apart from her permanent bilateral blindness. There were no signs of tumor recurrence. To our knowledge, this is the first documented case of bilateral blindness in a patient suffering from CST.