Transforming growth factor (TGF)-${eta}$-dependent apoptosis is important in the elimination of damaged or abnormal cells from normal tissues, especially in liver, in vivo. To investigate which gene expressions are critical for TGF-${eta}$-induced apoptosis in hepatocytes, gene expression profiling experiments were performed with TGF-${eta}$-treated and non-treated mouse hepatocytes AML12 cells. Findings showed that serum and glucocorticoid-inducible protein kinase1 (SGK1) expression is markedly downregulated during TGF-${eta}$-induced apoptosis. Findings confirmed that expression of SGK1 protein, as well as mRNA, is also markedly decreased with TGF-${eta}$ treatment. Infection of adenoviral vector encoding constitutively active SGK1 (CA-SGK1), but not kinase dead SGK1 (KD-SGK1), attenuated TGF-${eta}$-induced apoptosis. All of these results suggest that downregulation of SGK1 expression is critical for TGF-${eta}$-induced apoptosis in AML12 cells.