Attempts of the virus isolation from crusts of sheep suspected of ecthyma were made by means of infection of chick embryos and various tissue cultures. The attempts of infection of embryos remained unsuccessful. The cytopathic effect occurred most early and distinctly after infection of calf testis cell cultures. The virus proliferated in cell cultures and contained in crusts has been identified as the ecthyma virus by means of the electron microscopic examinations and sheep infection trials.