Two patients exhibiting bitemporal hemianopia due to chiasmal optic neuritis with pathological confirmation of noncompressive lesions are presented; the first due to a chronic, idiopathic demyelinating process, and the second a result of ethchlorvynol (Placidyl) toxicity. The literature regarding chiasmal optic neuritis is reviewed, and a discussion of other noncompressive causes of bitemporal hemianopia is presented.