Seventeen monoclonal antibodies (Mabs) reacting specifically with the cells infected with herpes simplex viruses type 1 (HSV-1) and type 2 (HSV-2) were characterized by a variety of immunological tests such as radioimmunoprecipitation, immunoblotting and virus-neutralization. The majority of Mabs was directed against glycoprotein B (anti-gB), six reacted with glycoprotein C (anti-gC) and one with glycoprotein G (anti-gG). Six anti-gB Mabs reacted with both types of HSV (anti-gB-1,2), two anti-gB and all the six anti-gC Mabs have been specific for HSV-1 (anti-gB-1 and anti-gC-1). The remaining two anti-gB Mabs and the anti-gG have been specific to HSV-2 (anti-gB-2 and anti-gG). Only three out of the seventeen examined Mabs neutralized the virus.