Objective: Hepatitis B virus ( HBV ) and hepatitis C virus ( HCV ) infections are important health problems throughout the world. These virus infections can cause chronic hepatitis, cirrhosis or hepatocellular carcinoma. The association of diabetes mellitus with liver disease was recognized many years ago and it has been documented in numerous studies. This association might be related to diabetes mellitus causing chronic liver disease or vice versa. It was reported that diabetes mellitus seems to be more frequent in chronic hepatitis C cases and patients who have type II diabetes mellitus have higher antiHCV seropositivity than normal. For this reason, frequency of HBsAg, antiHBs, antiHCV and its relation to the duration of diabetes, age of patients, and type of antidiabetics used was evaluated among our hospital diabetic outpatient clinic patients in the present study. Methods: Seventy-four type I and II diabetic patients followed by Haydarpaşa Numune Education and Research Hospital Diabetic's outpatient clinic between October 1999 and March 2000, participated in this study. The 3rd generation ELISA method was used for hepatitis markers detection with the " The Organon Technica " kits. Results: According to our study results, the frequency of HBsAg, antiHBs, antiHCV was found to be 4 %, 29 %, 4 % respectively among our study group. It was seen that antiHCV seropositivity in diabetic patients is higher than normal population. There is no statistical relationship between the hepatitis B and C markers positivity and age, duration of diabetes mellitus and type of antidiabetics used. Conclusion: As a result HBV incidence is similar to the normal population whereas HCV infection incidence is higher among diabetics than in the normal population. However to clarify the incidence of HCV infection among diabetic patients, we need further confirmative studies.