Colibacillosis is one of the major problems in poultry houses caused by avian pathogenic Escherichia coli (APEC) which is the main cause of high morbidity and mortality rates in poultry houses leading to high economic losses.  The present study was established to investigate the incidence of Escherichia coli (E. coli) infection in broiler birds suffering from yellowish-colored droppings, diarrhea, and soiled vent openings with or without septicemia signs. Aseptically, 200 samples were collected from the internal organs of diseased broiler chickens (liver, Heart, spleen, and yolk) at different farms in Ismailia governorate, 70 samples were E. coli positive with a 35% prevalence rate. The high prevalence of E. coli was recovered from yolk (40%), followed by liver (37.5%), heart (33.33%) and spleen (25%), respectively. A serological test was used to identify ten E. coli isolates as a slide agglutination test. The most predominant serotype was O44 (20%), O157 (20%), O119 (10%), O128 (10%), O78 (10%), O164 (10%), O145 (10%), O55 (10%).