Thirteen different species of bacteria were isolated and identified from the external body surface of Musca domestica collected from carrions and garbage dumps at Al Mansoureya, Giza, Egypt. The identified bacteria species were season and habitat dependent. The most frequent bacteria isolated from house flies collected from carrion or garbage in all seasons were Staphylococcus spp. and Esherichia coli. The total count of bacteria species was higher in summer season than in other seasons. Also, this count was higher on flies collected from carrion than on flies collected from garbage dumps. Chrysomya albiceps flies carried (11) different bacterial species on their external body surface all over the four seasons. Bacteria species were season and habitat dependent. The most frequent bacteria isolated from C. albiceps flies collected from carrion or garbage dumps in all seasons were Staph.spp. . The highest total bacterial count was recorded during spring season for bacteria isolated from Chrysomya flies collected from carrion. Four different bacterial species were identified on the external body surface of Sarcophaga carnaria in autumn 2014. The most frequent bacteria species isolated were Staphylococcus spp. Three different bacterial species were identified on the external body surface of Lucilia sericata in autumn 2014. The most frequent bacteria species was Staph. spp.. In general, 36 bacterial isolates from the different flies tested were identified. Bacteria species isolated from the external body surface of C. albiceps, S. carnaria and L. sericata were identified for the first time. The highest number of bacteria species (13) were isolated from M. domestica followed by (11) species from C. albiceps.