Diploic arteriovenous fistulas are rare arteriovenous shunts involving the skull, which often drain antegradely into the internal or external jugular veins. Diploic arteriovenous fistulas with marked cortical venous reflux are extremely rare. Here, we present the case of a patient with diploic arteriovenous fistulas with marked cortical venous reflux and a literature review. A 73-year-old woman presented with headache. Magnetic resonance angiography revealed abnormal signal intensity in the diploic layer of the left frontal bone. Digital subtraction angiography demonstrated a diploic arteriovenous fistulas located in the left frontal bone. The arteriovenous fistulas were fed by multiple branches of the left external carotid artery, mainly from the middle meningeal artery, branches of the ophthalmic artery, and the inferolateral trunk. The fistulas drained into the cerebral cortical veins surrounding the frontal lobe via an emissary vein of the frontal bone. With the femoral arterial approach, transarterial catheterization into the shunted diploic vein was performed with a small tapered microcatheter, and the arteriovenous fistulas were completely embolized with N-butyl-2-cyanoacrylate. The patient was discharged without complications. No recurrent arteriovenous fistulas were observed during the 12-month follow-up period. Endovascular treatment is an effective technique for the curative treatment of diploic arteriovenous fistulas.