We describe herein a case of an impending corneal perforation with a large descemetocele in a patient with previous penetrating keratoplasty (PKP) that subsequently was treated with an emergent lamellar keratoplasty using frozen preserved cornea. A 76-year-old male patient, who had a PKP, presented with a completely whitish and edematous graft accompanied by large epithelial defects. Although antibiotics and antiviral agents were tried for three days, the corneal stroma abruptly melted, except for the Descemet's membrane and endothelium. Cryopreserved corneal tissue that was kept at -80°C was thawed and sutured on top of the remaining Descemet's membrane and endothelium. Pathological and microbiological tests were conducted using the remaining donor and recipient corneal tissues. After tectonic corneal transplantation on top of a large descemetocele, a healthy graft and relatively clear interfaces between graft-host junctions were maintained without serious adverse reactions throughout 6 month follow-up period. Microbiological evaluations of donor tissue at the time of thawing and tissue preparation were done, and the results were all negative. Tissue that was taken intraoperatively from the recipient cornea also showed negative microbiological results. In conclusion, tectonic lamellar keratoplasty, using cryopreserved corneal tissue, only onto the remaining Descemet's membrane and endothelium in an emergent condition, was a safe and effective treatment.