Enterobacteria phage G4 is a bacteriophage capable of infecting susceptible bacterial cells. The phage was originally isolated from samples of raw sewage and infects E. coli. Its isometric capsid contains a single-stranded circular genome of about 5.5 kbp. Phage G4 bears high genetic and structural similarity to the phage ΦX174, though the two phage genomes are up to 39 percent different by sequence.