BSC-1 cells infected with a vaccinia virus recombinant containing the coding sequences for varicella-zoster virus (VZV) glycoprotein I (gpI) were analyzed by indirect immunofluorescence and immunoprecipitation for the expression and processing of gpI. The processing of gpI in cells infected with recombinant virus was the same as that observed during VZV infection. Immunofluorescence revealed localization of gpI to the membranes of recombinant virus-infected cells.