A study was undertaken to determine the prevalence and virulence of E. coli isolated from meat of domestic animals in some districts of Hanoi. A total of 90 samples of meat (pork, beef, and chicken) were taken from 11 market places in Gia Lam, Dong Anh, and Soc Son. Results showed that the percentage of meat samples meeting the hygienic standard was different among the threetypes of meat and the studied places. In detail, the percentage of pork and beef samples unsatisfying in terms of E. coli contamination was 53.33 percent with the highest found for chicken meat (60.0 percent). All (100 percent) of the isolates of E. colifrom meat samples had high toxicity, killing guinea pigs within 24 to 72 hours. There were three strains belonging to O26, O55and O157 antigen groups that could be hazardous to consumers. The results should warn consumers of the quality of meat available in the local market places.