The role of glycosylation in transport and expression of HSV-1 glycoproteins on the surface of HSV-1-infected African green monkey kidney cells was investigated by using tunicamycin (TM). A concentration of 0.05μg/ml of TM inhibited the replication of HSV-1 by greater than 99%. Immunoblot analysis of TM-treated and virus-infected cells indicated that 0.05μg/ml of TM blocked the addition of N-linked oligosaccharides into glycoproteins B,C and D. An immunofluorescence assay of TM-treated (0.05 and 0.1 μg/ml) and virus-infected cells demonstrated the presence of nonglycosylated gC, gD and a reduced amount of gB on the surface of infected cells. The results suggest that the addition of N-linked oligosaccharides on the studied HSV-1 glycoproteins was not necessary for their transport and expression on the virus-infected cell surface. © 1990.