Background: Antibiotic resistance has become a worldwide problem. Recently, there has been a global increase in infections caused by microorganisms resistant to multiple antibiotics. This has led to increases in morbidity and mortality and increased the cost of health care, which threatens to become unaffordable in developing countries. Behavioural factors, particularly the misuse of antibiotics; and lack of infection control practices in communities are the most common factors which lead to increase in antibiotic resistance. In Viet Nam, self-treatment is very common. Inappropriate use of antibiotics is frequent in the communities and in the hospitals. The development of antibiotic resistance is increasing in Viet Nam. Self-medication has been associated, in particular, with the overuse and inappropriate use of antibiotic drugs, and this has caused antibiotic resistance levels in Viet Nam to reach epidemic levels. This research was carried out in Bac Ninh province in order to identify the risk factors contributing to antibiotic resistance of enteric bacteria. Objective: The objectives of this study were identifying the risk factors that contribute to antibiotic resistance of bacteria; studying the pattern of use of antibiotics in the community; and determining the antibiotic susceptibility of enteropathogenic Echerichia coli (EPEC) strains isolated from the diarrhoeal patients.Methods: A hospital based cross-sectional study was performed. Suspected cases were diarrhoeal patient with greater than or equal to three diarrhoeal movements per day, who were admitted to Bac Ninh hospital from August to December, 2004. Study’s targets were defined as positive with EPEC in stool culture. Antibiotic sensitivity testing was performed on EPEC strains isolated. Exposure was defined as a case with EPEC strain resistant to at least one kind of the antibiotics tested. Non-exposure was defined as a case with EPEC strain sensitive to all of the antibiotics tested. Interviews were performed using a standard questionnaire collecting information regarding their behaviour concerning in antibiotic consumption, hygiene and socio-economic indicators. Results: There were 227 cases positive with EPEC among the 526 diarrhoeal patients admitted to Bac Ninh hospital during period time of this study. Among them, 171 cases were exposure and 48 cases were non-exposure (we did not include 8 cases, which were patients from outside of Bac Ninh Province). 68% of cases were children under 5 years of age. Following the conditional logistic regression model, being a patient with diarrhoea for more than 7 days (OR = 0.21; 95% CI: 0.05 - 0.93; P-value = 0.039); having a history of using antibiotic during the preceding 90 days (OR=5.41; 95% CI: 1.39 - 21.00; P-value = 0.015); having a low general knowledge (OR = 0.15; 95% CI: 0.04 - 0.52; P-value = 0.003); having used antibiotics in wrongly compared to medical instruction; and having been drinking un-boiled water were independently associated with antibiotic resistance of the EPEC strains isolated from the diarrhoeal patients. Among the 179 cases (78.85%) resistant to at least one kind of antibiotic, 157 cases (69%) were resistant to two or more of the antibiotics. There was a high rate of resistance to ampicillin (69.16%) and trimethoprim/sulphamethoxazol (67.84%). In this study, we also found some EPEC strains (9 strains) resistant to ciprofloxacin.Conclusion: Our study suggested that some factors such as: misuse of antibiotics; lack of knowledge about the signs of infectious disease; having a history of recently using antibiotics; drinking un-boiled water; and being exposed to unhygienic condition in living area were associated with antibiotic resistance of the disease – causing EPEC bacteria. There was a high proportion of resistance in the EPEC strains isolated from diarrhoeal patients. Antibiotic resistance has become an important problem. Multiple drug resistance (resistance with greater than or equal to two kinds of antibiotic) exists as a serious problem in Bac Ninh Province. These findings suggest that monitoring and control of resistance to antibiotics of bacteria are very important. Antibiotic sensitivity testing in the health care centres (at least in the hospitals) should be carried out as a routine to ensure that suitable antibiotics are used for treating infectious diseases. Patient should follow the doctor’s prescription. Over the counter sales of antibiotics should be stopped. Public communication is important to raise general knowledge of antibiotic use and encourage the population to use boiled water. Key words: Risk factors, antibiotic resistance, EPEC, diarrhoea, Viet Nam, developing countries.