Résumé : The polypeptide composition of three strains of infectious bovine rhinotracheitis virus, isolated from typical respiratory disease (IBR), has been compared with that of three strains isolated from the genital tract of cattle suffering from infectious pustular vulvovaginitis (IPV). All the IBR strains are similar to each other, but different from the IPV strains, which in turn were similar to each other. IBR isolates and IPV isolates differed in three polypeptides. © 1980, All rights reserved.