Abstract: The chronic macular edema, frequent in ocular Behcet's disease, is a treat to the visual outcome of the patients. We have investigated the origin, risk-factors and the outcome of macular edema in patents under immunosuppressors and corticosteroid therapy. This is a retrospective, case series study. In 1999,seventeen patients of the Behcet's clinic of Shariati hospital of Tehran who had macular edema were consecutively selected and included in the study. They were followed for two more years with ophthalmic examinations and fluorescein-angiographies. At the start of this study, the mean-duration of follow-up and treatment of the patients was six years (ranged between 1.5 and 17 years). The eyes were involved 14.7 months before the first consultation. In 25 of the 34 eyes the macular edema persisted up to the last visit. Only in four eyes it disappeared and in five eyes macular edema never was observed. Retinal perivasculitis, fluorescein leakage from the vessels + hyalitis was observed in all eyes with macular edema. Six eyes developed macular scars. The leakage from the retinal vessels was the cause of macular edema. In 85.8% of cases macular edema persisted despite our medical treatment. Other interventions such as laser-therapy should be undertaken to prevent chronic macular edema and its consequences.