The first results of a prospective study on 50 patients who were followed up 2, 4, 6, and 12 months after keratoplasty are reported. The patients received a human cornea transplant, which had been cultured in a modified MEM medium for up to 28 days. We observed that the loss of epithelium during organ culture leads to delayed regeneration after keratoplasty. This is especially important for patients who have had this problem almost before transplantation. The slower increase of visual acuity after keratoplasty with organ-cultured material is due to increased folding of Descemet's membrane. Nevertheless the best vision was usually reached within 6 to 12 months. We saw seven immune reactions by which five transplants were lost. A comparatively low rejection rate was observed especially in the group of high-risk patients (27.2%). Organ culture may therefore have some additional positive effects for these patients.