Four patients (six eyes) underwent successful corneal transplantations while receiving systemic cyclosporin. The six eyes had marked corneal vascularization preoperatively and in four, previous grafts had rejected. These eyes were therefore at high risk with respect to the likelihood of rejection and subsequent graft failure. All six grafts have remained clear (mean follow up twelve months) and only one minor rejection episode has occurred: this was easily reversed. The patients were monitored by repeated serum creatinine and trough serum cyclosporin levels. No significant side effects were encountered.