ABSTRACTHere, we characterize the genome ofMyxococcusphage Mx9, a lysogenic, short-tailed phage (genusLederbergvirus) phage infecting the bacterial hostMyxococcus xanthus, a model for bacterial evolution and development. The 53.5-kb genome has a GC content of 67.5% and contains 98 predicted protein-coding genes, including the previously characterized site-specific integrase gene (int).