Cyclosporin eye drops (2% in miglyol) were administered in 4 glaucoma patients for postoperative treatment following keratoplasty. In the course of the 2-year follow-up period, one patient evidenced an immunoreaction that led to clouding of the transplant. In 25 patients, Cyclosporin eye drops (2% in castor oil) were given in combination with low-dose dexamethasone eye drops (0.1%). During a mean follow-up period of 10 months (5 to 14 months), 4 transplants clouded as the result of an immunoreaction. The intraocular pressure was not influenced by the combination therapy in 21 patients who did not have a history of glaucoma but increased slightly in 3 of 4 patients who did. Since Cyclosporin A had no influence on the stromal wound healing, it was possible to remove the corneal sutures 5 months postoperatively. All patients developed keratopathia punctata and slight conjunctivitis. The epithelial defects, which often showed a vortex-like pattern, appeared at the end of the first postoperative week and were usually no longer detectable after 4 months. The tear production (Schirmer test) was not influenced or only slightly increased by Cyclosporin. Corneal infiltrates did not occur. If one compares the effects and side effects of Cyclosporin and dexamethasone, local application of Cyclosporin in combination with low-dose dexamethasone appears to be an effective treatment for corneal transplantation in Man.