Cyclosporin A (CsA), one of the most extensively investigated immunomodulatory agents, is widely used today in the treatment of various immunologically triggered dermatologic disorders. The immunologic basis for the therapeutic action of CsA depends on the suppression of lymphokine production by T cells. Due to its immunologic effects, this drug is also commonly preferred in Behcet's disease, especially with neurologic and ocular involvement. Since the course of this chronic disease presents remissions and exacerbations, drug therapy should be long term. Studies on the safety of long-term use of CsA in dermatologic diseases are limited. In this study, we aimed to evaluate the long-term use of CsA in Beh,et's disease without renal involvement. A total of 19 patients with ocular Beh,et's disease receiving CsA therapy for at least 1 year were included in this retrospective study. Changes in the parameters of renal function (creatinine clearance, creatinine level in serum), other adverse effects and their relation with cumulative CsA dosage were evaluated. The duration of CsA therapy and total dosage were not found to have a significant effect on the parameters of renal function, but, depending on clinical observations, the adverse effects seem to increase in the long term. We conclude that our results on renal function should be supported by renal biopsies.