Mitomycin C was used to induce temperate bacteriophage from three strains of Pediococcus acidilactici.The new bacteriophage, designated pa97, pa40, and pa42, were characterized based on morphology, DNA homology, and major protein profiles.Morphological attributes (small isometric heads with non-contractile tails) place these bacteriophages within the B1 group of the family Siphovirdae.Restriction endonuclease digests suggested that the bacteriophage genomes were linear molecules without cohesive ends, and between 33 and 37 kilobases in length.All three bacteriophages possessed one major protein with an estimated mass of 30 to 35 kilodaltons.Bacteriophage pa42 also contained a second major protein of approximately 47 kilodaltons.DNA-DNA hybridization showed bacteriophages pa40 and pa42 were homologous to each other, but not to pa97, suggesting that Pediococcus acidilactici bacteriophage fall into at least two different species.