In vivo scanning slit confocal microscopy was performed in a patient with Fusarium solani keratitis. Morphologically distinctive abundant filamentous structures were observed intrastromally. Confocal microscopy of the culture plate growing F solani from the patient's corneal scraping revealed filaments morphologically similar to the filaments observed in vivo. After 1 week of medical therapy, subsequent confocal microscopy showed an increased load of filaments, supporting the decision to perform a penetrating keratoplasty. Confocal microscopy confirmed that all of the fungus was eradicated. This aided in the decision to administer corticosteroids and quickly discontinue antifungal agents.