New proteins appearing after infection of cultured L929 cells with pseudorabies virus (PRV) were analyzed by SDS polyacrylamide gel electrophoresis. Analysis was facilitated by using a virus-cell system with marked inhibition of host protein synthesis after infection. Infected cells were pulsed during successive two hour periods through the infectious cycle with 35S-methionine. Proteins were extracted with detergent and analyzed on high resolution reducing gels. Thirty-four protein bands were resolved on gels of different concentrations that varied from 7 to 15 percent. Calculated apparent molecular weights of the protein peaks were not dependent on gel concentration except for very large or small sized proteins. Eight glycoproteins were resolved after labeling with 14C-glucosamine. The time course of incorporation of label was used as a measure of protein synthesis allowing the grouping of proteins according to the time of maximal synthesis. Several proteins shifted in MW during the course of infection, indicating possible post-translational cleavage or other minor modification.