Using the methods of Doughman, Sperling and Pels 66 human corneas were preserved up to five weeks in a modified tissue culture medium at +37 degrees C. The organ culture medium consisted of the following ingredients: Dulbecco Iscov's medium, 2% fetal calf serum, penicillin 100 IU/ml, Streptomycin 0.5 mg/ml, and fungizone 5 mg/ml. After culture the corneal endothelium was examined by light microscopy after staining with trypan blue 0.3% and alizarin red 1%. The number of dead cells was counted and the morphological alterations were described at 7, 14, 21 and 35 days. Biochemical analysis of the medium (pH, lactate, glucose) during storage has allowed the comparison of three kinds of storage: 50 ml, 20 ml, and 20 ml with 10 ml substitution weekly. After culture the number of dead cells did not exceed 1% at each period indicating that no dead cell was present at that time. Alteration of the cell shape and formation of rosette and joint meetings of 5 to 8 cells were the dominating morphological changes of the endothelial cells. The endothelial layer was intact and coherent on to 35 days culture. Endothelial cells loses during culture were not determined. The biochemical studies have shown the better quality (pH stability, anaerobic ratio) of storage in 50 ml medium or 20 ml 50% weekly substitution medium. This last kind of storage has given the best metabolic conditions for the preserved corneas. However for long period of storage up to 3-4 weeks, renewing 50% of the medium is found appropriate. At the end of this study a clinical trial is proposed.