− As it is needed to assay possible feasibility of extrapolation between in vivo and in vitro systems and to develop a new in vitro method for toxicity testing, we investigated global gene expression from both animal and cell line treated with thioacetamide (TAA) and compared between in vivo and in vitro genomic profiles. For in vivo study, mice were orally treated with TAA and sacrificed at 6 and 24 h. For in vitro study, TAA was administered to a mouse hepatic cell line, BNL CL.2 and sampling was carried out at 6 and 24 h. Hepatotoxicity was assessed by analyzing hepatic enzymes and histopathological examination (in vivo) or lactate dehydrogenase (LDH) assay and morphological examination (in vitro). Global gene expression was assessed using microarray. In high dose TAA-treated group, there was centrilobular necrosis (in vivo) and cellular toxicity with an elevation of LDH (in vitro) at 24 h. Statistical analysis of global gene expression identified that there were similar numbers of altered genes found between in vivo and in vitro at each time points. Pathway analysis identified several common pathways existed between in vivo and in vitro system such as glutathione metabolism, bile acid biosynthesis, nitrogen metabolism, butanoate metabolism for hepatotoxicty caused by TAA. Our results suggest it may be feasible to develop toxicogenomics biomarkers by comparing in vivo and in vitro genomic profiles specific to TAA for application to prediction of liver toxicity.