Report on 11 patients who underwent penetrating keratoplasty and were treated with Cyclosporin A for an average of 6 months because of excessive superficial and deep vascularization of the recipient cornea. In none of the patients was a permanent Cyclosporin A-induced side-effect observed. After an average follow-up period of 11 months 9 grafts remained completely clear; however, an allograft-reaction occurred in 2 cases in spite of the immunosuppressive therapy.