&NA;The authors report a case of a ventricular oligodendroglioma associated with a cortical arteriovenous malformation. The patient presented with subarachnoid hemorrhage. Computed tomographic scan showed an intraventricular hyperdense lesion, mimicking a hematoma. Angiography revealed a superficial arteriovenous malformation in the right parietal lobe, unrelated to ventricular cavities. Both lesions were treated during the same operation. The diagnostic difficulties and the significance of this uncommon association are discussed. (Neurosurgery19:125‐128, 1986)