THIS TRIAL was to investigate the outbreak of acute diarrhea in poultry birds at Ismailia, and North Sinai for detection and characterization of shiga toxin Escherichia coli (STEC). Two hundred samples from natural diseased and emergency slaughtered broiler chicks were collected from poultry farms in Ismailia and North Sinai. All cases were subjected to post-mortem, bacteriological examination, hematological and biochemical analysis. Escherichia coli(E. coli) was isolated and identified from cloacal swabs, intestinal contents, heart blood and liver of  poultry birds that died due to acute diarrhea. Phenotypic characterization was done by standard bacteriological and biochemical techniques. All the isolates were serotyped based on their somatic antigens. Virulence genes (stx1, stx2, eaeA and hlyA) were detected by multiplex PCR assay.A total of 20 E. coli isolates were obtained, of which O6(6), O111 (2), O55 (3), O114(2), O15(3), O125(2), and untyped (2). Out of 20 serotype, O6 carried one virulence gene of stx1 and O125 carried one virulence gene of stx 2. The other all serotype didn't carried virulence gene. The biochemical analysis of blood showed increase in AST and ALT and a significant change inprotein. Hypoalbuminemia, was observed and increase of serum uric acid, creatinine and phosphate as well as decrease in level of potassium,calcium and  sodium. Blood examination revealed a significant decrease in RBcs count, hemoglobin (Hb) concentration and packed cell volume (PCV) in the affected birds indicate anemia of  microcytic hypochromic.It could be concluded thatthe isolated bacterial pathogens play an important role in causing diseases in poultry and human consumer due to presence of toxin and losses in poultry farms at Ismailia and North Sinai.