Between 1973 and 1987 we recorded 300 cases of Behçet's disease with fundus changes. Our routine preview of each case included examination with the Goldman three-mirror contact lens, ophthalmoscopy, referral for laboratory tests, color fundus photography and, most importantly, fluorescein angiography. The ophthalmological findings led to the proper diagnosis in 254 (85%) of our cases. Fluorescein angiography revealed incipient fundus changes in 38 eyes of 19 medically diagnosed patients with no visual complaints and normal fundi on ophthalmoscopy. Eighty-six percent of our cases had or developed diverse fundus changes bilaterally. The fundus changes we encountered most frequently were hyperemia of the optic disc, macula edema, retinal edema, vascular sheathing, retinal exudate, and retinal hemorrhage. With the exception of eyes with very poor prognoses, only 184 of the 403 eyes that were followed up for 3-120 months (median 12) experienced new insults in the posterior segment; 40 of these became totally blind while 59 maintained their visual status. Early diagnosis is necessary for proper treatment patients with Behçet's disease. Fluorescein angiography is required for early diagnosis and for monitoring the posterior segment involvement closely. This is the most characteristic and often the most serious consequence of Behçet's disease; it may also the first indicator of the disease.