Background: Herpes simplex virus (HSV) infection of the cornea is a leading cause of blindness in occidental countries and a common recurrent manifestation of it is the immune stromal keratitis (ISK). However, it is not known whether active viral replication occurs during the acute phase of the disease, because isolation of the virus by conventional culture techniques has not been accomplished. Aim: To establish the presence of HSV in patients with ISK. Material and methods: Fourteen corneal swabbing samples, from active diseased eyes of patients with clinical diagnosis of ISK, were submitted to Herpchek® and PCR for the identification of HSV antigens and genome. Results: All ISK samples were negative by both techniques. Conclusions: It was not possible to identify HSV antigens nor their genome by the methodology used. It is likely that, they can t be detected in corneal superficial layers or probably there is no viral replication at this stage of the disease, so antiviral therapy should be reconsidered. (Rev Méd Chile 2001; 129: 259-63).