Two patients, a 48-year-old woman and a 44-year-old man, with fungal keratitis were treated with orally administered ketoconazole, a new antifungal agent. In both cases healing and regression of the corneal ulcer began four or five days after initiation of ketoconazole treatment (300 mg/day). The clinical signs of corneal infection disappeared after eight (Case 1) and three (Case 2) weeks and visual acuities improved markedly (from counting fingers at 5 cm to 20/30 in Case 1 and from 20/30 to 20/16 in Case 2). The levels of serum glutamic oxaloacetic transaminase and serum glutamic pyruvic transaminase increased slightly during the course of treatment (total dosages: 13,000 mg in Case 1 and 4,700 mg in Case 2), but no other systemic or topical signs of toxicity or adverse reactions were noted in either case.