To establish a human hepatic cell line for a convenient reporter gene assay of arylhydrocarbon receptor (AhR) activators, the chimera plasmid containing xenobiotic responsible element (XRE), minimal SV40 promoter, and luciferase reporter gene and the expression vector pRC/CMV containing a neomycin-resistant gene were co-transfected into a human hepatoma cell line, HepG2. Then, antibiotic (G418)-resistant HepG2 cells were selected and cloned. A cell clone, HepG2-A10, showed the highest responsibility to 3-methylcholanthrene (MC)-mediated induction of luciferase among the clones obtained. Expression levels of luciferase activity in HepG2-A10 cells were increased in a dose-and time-dependent manner by treatment with either MC, an AhR-ligand type activator, or omeprazole (OME), a non-AhR ligand type activator. In addition, expression levels of cytochrome P4501A subfamily genes (CYP1A1 and CYP1A2) were also increased in a dose-and time-dependent manner by treatment with MC. The presentˆndings demonstrate that a newly established human HepG2-A10 is a useful cell line for a convenient reporter gene assay of AhR activators.