Herpes simplex virus type 2 (HSV-2) strains inhibit the synthesis of both DNA and protein of the host cell more rapidly than HSV-1 strains. Several intertypic HSV-1 X HSV-2 recombinants and parental strains were examined for their ability to inhibit rapidly the synthesis of host protein and DNA. The two functions cosegregated in all of eight recombinants tested and are therefore controlled by the same gene or by different genes in the same region of the viral DNA.