The prevalence of exposure to aflatoxin, hepatitis B virus (HBV), and hepatitis C virus (HCV), three important risk factors for hepatocellular carcinoma, was examined in Guinea, West Africa. A total of 75 sera were collected from men living in the Kindia region of lower Guinea. The sera were analysed by immunoassay for aflatoxin covalently bound to serum albumin as a marker of aflatoxin exposure. Over 90% of the sera contained detectable adduct levels, the highest level being 385 pg aflatoxin B1-lysine equivalent per mg albumin. Eleven subjects (14.7%) were positive for hepatitis B surface antigen in the serum and these subjects had a tendency to have higher aflatoxin-albumin adduct levels than the other subjects (mean level 70.4 pg/mg compared to 44.1 pg/mg), but the difference was not statistically significant (P = 0.23). Eight subjects were positive for antibodies to HCV antigens and, interestingly, seven of these were from one ethnic group, Mandinka (25% prevalence). These data demonstrate that all three exposures are prevalent in Guinea and that the prevalence of these risk factors is comparable to that observed in other countries in West Africa. It is now important to assess the public health impact of these exposures in this country.