A total of 160 animals, water, food and human samples were collected and examined for the presence of Escherichia coli O:157. The samples included 53 fecal swabs of farm animals (19 sheep. 18 buffaloes, 16 cattle), 21 water (6 wells, 7 public and 8 River Nile), 46 food (14 raw milk, 12 chicken meat and 20 crayfish, Procambarus clarkii), 20 surgically excised appendices and 20 human fecal swab samples. E. coli 0:157 was detected in 3 out of 18 (16.7%) buffalo fecal samples, meanwhile, E. coli O:157 was neither detected from any examined cattle nor sheep fecal samples. Only one River Nile water sample out of 8 (12.5%) was positive for E. coli O:157, but the well and public water samples were free from  it. Moreover, two isolates were recovered from raw milk and chicken meat samples (one isolate, each) with the percentages of 7.1% and 8.3% respectively. On the other hand, E. coli O:157 was not molecular similarity coefficients of human, bovine, avian and water origin E coli O:157 strains were assessed. Similarity coefficient was identical (100%) between human and buffalo strains. Clonal relatedness ranged from 58 to 92% among other strains. The zoonotic importance of the isolated E coli O:157 was discussed. detected from any examined crayfish samples. Regarding human samples, one isolate from an appendix and 2 from human stool were identified with the percentage of 5% and 10%, respectively. Moreover, hemolysis was observed in 6 out of 9 (66.7%) E coli O:157 isolates recovered from different sources. Meantime, E. coli non-O157 were also identified from farm animal fecal swabs, River Nile water, food and human samples with varying percentages. Histopathological ex- amination of appendices which were positive to E coli O:157 revealed inflammatory cells infiltration in mucosa and submucosa. Random Amplified Polymorphic DNA (RAPD) Polymerase Chain Reaction (PCR) fingerprinting of the isolated strains from different sources were carried out using five multiplex arbitrary primers Molecular reproducibility of RAPD-PCR assay for E.coli O:157 strains recovered from different sources produced many bands ranged from 1 to 6 in number and 212 to 2000 bp in molecular weight. The molecular similarity coefficients of human, bovine, avian and water origin E. coli O:157 strains were assessed. Similarity coefficient was identical (100%) between human and buffalo strains. Clonal relatedness ranged from 58 to 92% among other strains. The zoonotic importance of the isolated E. coli O:157 was discussed.