This study describes the isolation of temperate B. anthracis phages, from 4 out of 20 B. anthracis strains screened, by use of the inducing agents mitomycin C and UV light. Phage phi 20 isolated from B. anthracis Sterne 34F(2) (pXO1(+) pXO2(-)) was shown to have double-stranded DNA of size 48756 bp and a restriction site map showing nine sites for enzymes BamHI, Bg/II, and SstI is included. The phi 20 genome was found to exist as a plasmidial prophage and the phage itself to have a polyhedral head of diameter 65 nm and tail 217 nm long and 15 nm wide.