Of 11 patients (8 women and 3 men, ranging in age from 16-48 yr) who had sarcoidosis of the optic nerve that caused decreased visual acuity and visual field abnormalities, only 2 were known to have sarcoidosis at the time the visual impairment developed. Four patients had granulomas involving the optic nerve head, 4 had granulomatous inflammation of the orbital or intracranial optic nerve or chiasm, and 3 had retrobulbar neuritis. All 11 patients had histologically confirmed idiopathic noncaseating granulomatous inflammation and 8 of the 11 had abnormalities compatible with sarcoidosis in chest roentgenograms. In the 3 patients in whom the serum level of angiotensin-converting enzyme was determined, it was increased in 1 and normal in the other 2. Computed tomography of the anterior visual pathways was the single most useful neurodiagnostic study. Treatment with corticosteroids was beneficial in 6 of the 11 cases. These cases demonstrated that sarcoidosis should be included in the differential diagnosis of any inflammatory or compressive lesion involving the anterior visual pathways.