Escherichia coliare the most common cause of diarrhea in calves. Diarrhea in calvesremains one of the most important problems faced by livestock, causing great economic losses. Some strains ofE. coli characterized by the presence of specific virulence factors including haemolysin production, resistance to bactericidal effects of serum and Congo red binding activity. In this studyfecal samples were collected from 115 diarrheic calves aged from 3 days to one year and from different localities in Egypt along the period from February to August 2015.The prevalence of E. coli in diarrheic calves was 72.2%. 39.8% of isolated E. coli were haemolytic to sheep blood agar, 68.7% were serum resistant, 100% showed Congo red binding activity.