Eight cases of homonymous hemianopsia due to chiasmal compression by intracranial aneurysms have been reported in the literatures. Two similar cases were experienced in our clinic and reported. Of the total 10 cases, 8 were giant aneurysms--over 2 cm in diameter--and 9 cases were aneurysm developing medially from the internal carotid artery. Visual disturbances in all the 10 cases were incongruous homonymous hemianopsia without macula sparing. It should be noted that the existence of aneurysm is possible, in patients with homonymous hemianopsia, even when there is no other clinical evidence of mass lesion.