In this paper, utilization of hyperbaric oxygen in the treatment of corneal neovascularization due to herpes simplex keratitis is presented. A 20- year-old male patient applied to ophthalmology clinic with complaint of blurred vision in his left eye. On his ophthalmologic examination, deep and superficial corneal neovascularization and a central corneal ulcer were detected. The patient was formerly diagnosed as herpes simplex keratitis. Visual acuity was 20/400 in the affected eye. Topical steroid treatment was not administered due to its adverse effects. Hyperbaric oxygen treatment was started after informed consent was obtained from the patient. A total of 20 sessions of hyperbaric oxygen treatment was applied to the patient during a four-week period. Corneal neovascularization was completely regressed and corneal ulcer healed with a corneal scar (leucoma). Visual acuity increased to 20/40. Hyperbaric oxygen treatment might be beneficial in treatment of corneal neovascularization, however its effectiveness should be confirmed with randomized controlled trials in order to place it in standard treatment protocol.