In a prospective, open clinical trial, we studied long-term effects of cyclosporine (CsA) on the optic nerve and retinal vasculitis in 14 Behçet's disease patients. Patients were treated with CsA and corticosteroids for a mean period of 42 months, with a range of 36 to 52 months. They received an initial CsA dosage of 7 mg/kg/day for three days, followed by 5 mg/kg/day, and prednisone 1 mg/kg/day for three to five days, tapered to 0.4 mg/kg/day. CsA was tapered when clinical response was noted. Improvement occurred in visual acuity and visual field defects secondary to papillitis, optic neuritis, macular neuroretinitis, and retinal phlebitis, but not with retinal arteritis. Despite a 12/14 (85%) exacerbation rate, no permanent liver or renal lab tests abnormalities were noted. Intermittent, low-dose CsA therapy may be considered in treatment of acute retinal and optic nerve vasculitis assisted with Behçet's disease.