Polyclonal antiserum 8101 against aflatoxin B₁ (AFB₁) was raised in New Zealand white rabbits after injection of bovine serum albumin-AFB, conjugate. Competitive ELISA (enzyme linked immuno-sorbent assay) demonstrated that antiserum 8101 has the highest binding for AFB₁ (50% inhibition at 170 fmol) and aflatoxicol II (50% inhibition at 112 fmol). It also reacts with other aflatoxins such as AFB₂, AFG₁, AFG₂, and aflatoxin metabolites (AFM₁, AFM₂, AFP₁, and AFQ₁), but it does not cross-react with AFG_(2a). Using this antiserum, aflatoxins were quantitated in 100 urine samples of undergraduate students at the College of Pharmacy, Sung Kyun Kwan University, Republic of Korea. By ELISA, AFB₁ and its metabolites were detected in human urine samples (N=100, male=89, female=11, ages=20∼31 yrs) with a range of 1.4∼200.6 ng/㎏/day (mean± SD=18.11 33.01 ng AFB₁/㎏/day in males, 3.82±2.65 ng/㎏/day in females). Assuming that urinary excretion is about 7.6% of AFBI intake (Groopman et al., 1992), we estimated that Koreans were daily exposed to a total dietary AFB₁ of 240.20±438.67 ng/㎏/day in males and 50.35±29.88 ng/㎏/day in females, respectively. When the human monitoring data was applied to a linear regression model of Y=21.67X-10.04 {Y=liver cancer incidence per 100,000, X=Log AFB₁ intake (ng/㎏/day), r=0.99} developed from previously reported epidemiological data, calculated liver cancer Incidences attributed to AFB₁ exposure were 41.56/100,000 in males and 26.84/100,000 in females. The incidences were similarly correlated with liver cancer mortality rates of 43.43/100,000 in males and 11.23/100,000 in females in Korea. These results suggest that aflatoxin exposure may be an important risk factor for the high incidence of liver cancer in Korea.