In this paper we describe the ability of monoclonal antibodies to prevent herpetic stromal or interstitial keratitis following corneal infection in an outbred mouse model. Monoclonal antibodies recognizing antigenic determinants on glycoproteins B, C, D, and E of herpes simplex virus type 1 were injected intraperitoneally into CF-1 outbred mice 24 or 48 h following inoculation of the cornea with the RE strain of herpes simplex virus type 1. Passive, postexposure immunization with monoclonal antibodies had little effect on the severity of the initial corneal infection or the frequency of latent viral infections in the trigeminal ganglia, except for virus-neutralizing antibodies specific for glycoproteins B and D. A significant correlation was found between the severity of epithelial keratitis and the frequency of latent ganglionic infections. However, immunization with monoclonal antibodies protected the mice against encephalitis and prevented the development of necrotizing stromal keratitis that leads to permanent corneal scarring and blindness. This form of herpetic ocular disease does not respond to antiviral chemotherapy. Since nonneutralizing monoclonal antibodies were just as effective in prevention of encephalitis and stromal keratitis as ones that neutralized the virus in vitro, and antibodies were not administered until 24 or 48 h after corneal inoculation, we suggest that inactivation of infectious virus is not the only protective mechanism in this model.