The staphylococcal Panton-Valentine leukocidin (PVL) genes, [lukS-PV-lukF-PV], exist on the genome of a temperate bacteriophage phiPVL isolated from mitomycin C-induced Staphylococcus aureus V8 (ATCC 49775) (Kaneko, J., Kimura, T., Kawakami, Y., Tomita, T., Kamio, Y., 1997b. Panton-Valentine leukocidin genes in phage-like particle isolated from mitomycin C-treated Staphylococcus aureus V8 (ATCC 49775). Biosci. Biotechnol. Biochem. 61, 1960-1962). In this study, the complete nucleotide sequence of the phiPVL genome was analyzed, and the att sites (attL, attR, and attB) required for site-specific integration of phiPVL into the host chromosome were also determined. The linear double-stranded phiPVL genome comprised 41401bp with 3' staggered cohesive ends (cos) of nine bases and contained 63 ORFs, among which the regulatory proteins involved in DNA replication, structural proteins, a holin, a lysin, an integrase, and dUTPase, were tentatively identified by the comparison of the deduced amino acid sequences and by the analysis of the proteins isolated from phiPVL particles. The [lukS-PV-lukF-PV], attP, and int (integrase gene) of phiPVL were all located very close to one another within a 4.0-kb segment on the genome in the order given, and this segment was located at the center from the left and the right cos sites. In addition, the attP region contained five direct repeat sequences that showed a high degree of homology with the recombinase-binding sites of some other S. aureus bacteriophages. The phiPVL genome was found to integrate into an ORF encoding an unknown protein comprising 725 amino acid residues with two leucine zipper-like motifs.