We have isolated and characterized a double-stranded DNA bacteriophage (TPC-1) of Bosea thiooxidans, a facultative sulfur chemolithotrophic bacterium. The name 'thiophage' is introduced for phage(s) infecting sulfur chemolithotrophic bacteria. Electron micrographs showed the phage particle with an icosahedral head and a very short wedge-like tail. TPC-1 is classified as the C1 morphotype of the Podoviridae family. Restriction map and terminal ends detection by end fill labeling of the TPC-1 genomic DNA showed that the genome is linear with 5' protruding cohesive termini. Contour length mapping of the DNA genome also revealed it to be a linear fragment with size ( approximately 44 kb) corresponding with the size estimated from restriction fragment analyses and proved the non-redundant nature of the linear genome topology. In colorless sulfur chemolithotrophic microorganisms, TPC-1 is the first report of a generalized transducing thiophage.