Background/aims: Hepatocellular carcinoma is the fifth most common cancer and a major public health problem worldwide. Differences in distribution of hepatocellular carcinoma incidence are probably due to different levels of exposure to hepatocellular carcinoma risk factors: chronic infections with hepatitis B virus (HBV) and aflatoxin exposure in developing countries, and smoking and alcohol abuse in developed countries. Aflatoxin is one of the most important of the environmental toxins that contribute to the pathogenesis of hepatocellular carcinoma, especially in the regions where dietary foodstuff's (peanuts, corn, Brazil nuts, pistachios, spices and figs) are highly contaminated. High aflatoxin levels have been shown in the foodstuffs that are produced in our country. The specific aim of this study was to assess the rate of aflatoxin exposure and to determine some clues about aflatoxin metabolism by measuring and comparing the levels of carcinogenic forms in healthy subjects, in different stages of viral disease, and in different viral hepatitis types. Methods: This was a cross-sectional observational, single-center study. A total of 203 (male 1 female: 119184) viral hepatitis patients who were consecutively admitted to Ankara University, School of Medicine, Gastroenterology Clinic, between January 2006 and June 2007 were enrolled into the study. Sixty-two healthy subjects (male 1 female: 33129) with normal blood chemistry and negative viral serology served as controls. Chemical forms AFB1, AFB2, AFG1, and AFG2 were assessed in plasma of study participants by high-performance liquid chromatography. Results: AFB1, AFB2, AFG1, and AFG2 were detected in 24.6%, 17.2%, 22.7%, 18.2% of the 203 patients, respectively, and were significantly higher than in the control group for all chemical forms. Percentage of AFB1-positive patients was significantly higher than in the control group irrespective of disease stage. There was no significant difference between chronic infected patients, cirrhotic patients and patients with Hepatocellular carcinoma with respect to percentage of aflatoxin-positive individuals. Conclusions: With this study, we have documented that in viral hepatitis patients, aflatoxin exposure is significantly higher than in healthy subjects in Turkey and it may play an important role in the development of hepatocellular carcinoma. Thus, large studies exploring the relation between aflatoxin exposure, viral hepatitis status, and risk of hepatocellular carcinoma development are needed.