Lactoferrin inhibits bacterial growth in the conjunctival sac. However, its antiviral function particularly in ocular tissue has not been reported in the literature. We studied whether lactoferrin inhibits infection of herpes simplex virus type-1 (HSV-1) in vitro using Vero cell monolayer. We also tested the inhibitory effect of lactoferrin on HSV-1 infection in the mouse cornea. Lactoferrin prevented HSV-1 plaque formation. Administration of topical 1% lactoferrin prior to the virus inoculation suppressed infection on ocular tissue, however it did not inhibit propagation of the virus.