The tumor necrosis factor (TNF)-related apoptosis-inducing ligand(TRAIL) has recently been implicated in the death of hepatocytes during HBV infection, but the molecular mechanisms are not well understood.To determine the potential roles of TRAIL in HBV infection, we examined the effects of HBV complete genome and its X protein (HBx), C-terminally truncated middle hepatitis B surface protein (MHBs(t)) and core antigen (HBc) on TRAIL-induced hepatocyte apoptosis.Using the TUNEL assay, we found that HBV complete genome or HBx significantly increased TRAIL-induced apoptosis through up-regulating Bax.