The viral glycoproteins of infectious laryngotracheitis virus, an alphaherpesvirus, were the dominant antigens recognised by immune chickens. Glycoproteins with molecular weights of 205, 160, 115, 90, 67, 60, and 52k reacted strongly in Western blotting studies with a majority of chicken antisera. Viral glycoproteins immunoprecipitated using monoclonal antibodies were also able to elicit a delayed-type hypersensitivity reaction in chickens previously vaccinated with a live vaccine. The 60 k glycoprotein alone and the antigenically related family of higher molecular weight glycoproteins (205, 160, 115, 90, and 85 k) both elicited significant increased in the thickness of the wattles of immune cockerels. Because the glycoproteins induce both antibody and cell-mediated immune responses they may prove to be important protective immunogens in a subunit vaccine.