Sequencing of approximately one half of the genome of acipenserid herpesvirus 2 (AciHV-2), which is a member of the genus Ictalurivirus in the family Alloherpesviridae, revealed that the gene organization is very similar to that of ictalurid herpesvirus 1 (IcHV-1), the founder member of the genus. The sequenced region encodes the AciHV-2 homologues of IcHV-1 ORF24 to ORF69. It contains 46 predicted protein-coding regions, including 12 that seem to have a homologue in every alloherpesvirus genome sequenced to date. Phylogenetic tree reconstruction, based on the concatenated sequence of these conserved genes, implied that the family Alloherpesviridae is composed of three major clades and could be subdivided into three subfamilies.