We determined the complete genome sequence of epidemic keratoconjunctivitis (EKC)-related human adenoviruses (HAdVs). We analysed a total of 12 HAdV strains; three prototype strains and two HAdV-8, three HAdV-19 and three HAdV-37 clinical isolates from EKC patients in Japan, and one novel serotype of HAdV. Genome organization of these serotypes was identical to those of the recently determined HAdV-19 and HAdV-37. The identities of the whole genome were over 99 % among strains from the same serotype, except for HAdV-19p, which is not associated with conjunctivitis, resulting in the formation of a distinct cluster in the phylogenetic analysis. The penton, loop 1 and loop 2 of hexon, early region 3 (E3) and fiber were hypervariable regions between serotypes. Results suggest that the HAdV-19 clinical strain is a recombinant of HAdV-19p-like and HAdV-37-like strains, and that the acquisition of the penton, E3 or fiber may be related to ocular tropism.Adenoviruses are nonenveloped, double-stranded DNA viruses with icosahedral capsids (Swenson et al., 2003). Human adenoviruses (HAdVs) belong to the genus Mastadenovirus of the family Adenoviridae and are classified into six species, A to F (HAdV-A to HAdV-F) (Benkö et al., 2000;Wold & Horwitz, 2007). Adenoviral conjunctivitis is mainly caused by HAdV-3 (in HAdV-B), HAdV-4 (in HAdV-E), and HAdV-8, , with the three HAdV-D serotypes being known to cause epidemic keratoconjunctivitis (EKC). HAdV-8 is the original causative agent of EKC and remains the predominant HAdV serotype isolated in association with EKC in many countries (Ishii et al., 1987;Chang et al., 2001;Vainio et al., 2001;Aoki & Tagawa, 2002; Jin et al., 2006). In Japan, although HAdV-8 and HAdV-19 have been described, a novel serotype of HAdV recently isolated from EKC patients and HAdV-37 are the predominant causative serotype of EKC in Japan (Higuchi et al., 1987;Aoki & Tagawa, 2002;Ishiko et al., 2008;Kaneko et al., 2008).Nucleotide polymorphisms in HAdV strains isolated from EKC patients can be classified into discrete genotypes within a specific HAdV serotype on the basis of their restriction endonuclease cleavage pattern (Wadell et al., 1980;Adrian et al., 1986). It has been speculated that the appearance of new genotypes might contribute to the incidence of outbreaks of each serotype (Aoki & Tagawa, 2002;Ariga et al., 2005). DNA sequence analysis has allowed us to appreciate the molecular evolution of HAdV in greater detail, and revealed that the penton, hexon and fiber genes were the most variable among the different serotypes (Pring-Akerblom & Adrian, 1995;Arnberg et al., 1997;Ebner et al., 2005;Madisch et al., 2005Madisch et al., , 2007 MiuraOchiai et al., 2007). The complete genome sequences of 24 HAdV serotypes 2, 3, 4, 5, 7, 9, 11, 12, 14, 16, 17, 19, 21, 26, 34, 35, 37, 40, 41, 46, 48, 49 and 50) have now been determined.In this study, we describe the complete genome sequences of the prototype strains HAdV-8p, HAdV-19p and HAdV37p together with a novel HAdV serotype and eight clinical