Sheathing of peripheral retinal veins occurs in 10 to 20% of patients with multiple sclerosis and can be seen at any point in the progression of the disease. This finding may represent the retinal correlate of the vascular lesions that are present in the central nervous system of patients with multiple sclerosis. Its pathogenesis is still uncertain. In this paper it is registered the occurrence of retinal periphlebitis as one of the initial manifestations of a patient with multiple sclerosis and it is discussed the diagnostic implications of this finding.