Rabbit kidney cells infected with pseudorabies virus synthesize proteins that migrate electrophoretically in polyacrylamide gels as several distinct peaks. One of these peaks consists of proteins which have a molecular weight of approximately 120,000 daltons and make up the major component of the viral particles. In addition to these proteins, purified preparations of pseudorabies virions also probably contain proteins of smaller molecular weight migrating as minor peaks in the polyacrylamide gels. © 1969.