Corneoscleral excision is the most common harvesting technique used in France before keratoplasty. We report two cases of corneal button epithelial invasion during organ culture caused by an excision that was too small. Two corneas stored for 23 days in organ culture at 31 degrees C had a cellular proliferation on the surface of Descemet's membrane. Cornea button diameters were respectively 11 and 13mm. The epithelial origin of the invasion was confirmed by examining the flat mount of Descemet's membrane by inverted microscopy and standard histopathology. The authors discuss the origin and the potential consequences of the epithelial invasion and emphasize the importance of good corneal harvesting recommendations before keratoplasty.