Twelve slow-growing virus isolates propagated in tissue culture from cattle with epididymitis and vaginitis were identified as herpes viruses by virtue of their biological, physicochemical and morphological characteristics. None of the 12 virus strains proved to be serologically related to the infectious pustular vulvo-vaginitis-infectious bovine rhinotracheitis (IPV-IBR) virus, but a further 3 strains included in this study were identical with IPV-IBR virus. Three of the slow-growing virus strains caused a mild anterior vaginitis when deposited in the vagina of heifers. A pool of 10 slow-growing viruses plus a strain of IPV-IBR virus produced anterior and posterior vaginitis in a heifer. The results are discussed in the light of the original description of vaginitis in the "epivag" syndrome.