Eight strains of a new intermediate adenovirus were isolated in the course of an investigation of conjunctivitis in Hiroshima City, Japan. The strain was first isolated in July 1986. All eight strains were isolated from conjunctival swab samples from patients with conjunctivitis, mainly epidemic keratoconjunctivitis. The virus was typed as adenovirus type 22 in neutralization tests and was related closely to types 10, 19, and 37 in hemagglutination inhibition tests. The DNA cleavage patterns of the eight strains with nine restriction endonucleases were the same with one exception but different from those of the above serologically related species. We conclude that the intermediate adenovirus is a new etiological agent of conjunctivitis, mainly epidemic keratoconjunctivitis.