Beauveria bassiana is a hyaline Hypomycetes, which is known as an insect pathogen causing infections in silkworm. It is a rare opportunistic pathogen of human accounted for pulmonary infection, keratitis, and deep tissue infection. We report the first case of B. bassiana keratitis in Korea. A 64-year-old man with a 10-year history of herpetic keratitis was referred for the treatment of infectious keratitis in the right eye. Corneal scrapings showed septate hyaline hyphae on calcoflour white-KOH preparation and their cultures grew B. bassiana. At the beginning, the patient was treated empirically with an antiviral and antibiotics, and then the treatment was changed with antifungal agents including voriconazole, when the culture results were available. Since the inflammation had been aggravated despite medical treatments, he underwent a penetrating keratoplasty (PKP). The excised button of cornea showed the hyphae. The treatment with voriconazole was continued until 2 months after PKP, and fungal keratitis did not relapse during a 6-month follow-up period. (Korean J Clin Microbiol 2007;10:73-76)