Purpose: Corneal collagen crosslinking (CXL) is effective not only in halting the progression of keratoconus but also in management of infectious keratitis. However, as far as we can ascertain, there are no reports of CXL for the treatment of severe infectious keratitis in Japan. Thus, we report 2 cases in which CXL was effective for infectious corneal ulcer. Cases: A 82-year old man and 76-year-old woman. Both of which were treated with local antibiotic therapy; however, the therapy was not empirically effective. Thus, we performed CXL following the standard Dresden protocol after obtaining informed consent from each case. Two weeks after CXL, slit-lamp examinations revealed improvements of corneal transparency and keratitis in each case. No serious complications such as corneal perforations and infectious recurrences occurred after the treatments. Conclusion: Two cases of infectious keratitis improved in corneal opacity and had showed inhibitory effect on infected cornea. CXL seems to be an effective therapeutic alternative in resistant cases of infectious keratitis, although the exact etiology of this effective treatment remains unclear.