Acute pancreatitis induces liver injury by upregulating Kupffer cell-derived Fas/FasL; on the other hand, acute pancreatitis induces apoptosis of Kupffer cells via NF-kappaB-dependent pathways. The balance between upregulation of Fas/FasL and Fas/FasL-induced apoptosis of its originator cell may determine the severity of pancreatitis-related liver injury. The aim of our study was to determine the role of p65 NF-kappaB/RelA in pancreatitis-induced Kupffer cell apoptosis. Acute pancreatitis was induced in NIH Swiss mice by a choline-deficient ethionine-supplement (CDE) diet. In vitro mouse Kupffer cell line was transfected with p65 siRNA and treated with pancreatic elastase to mimic pancreatitis. CDE pancreatitis upregulated nuclear translocation of p65 NF-kappaB/RelA, Fas/FasL, caspase-3, and DNA fragmentation in mice livers (all P < 0.001). In vitro, pancreatic elastase mimicked CDE-pancreatitis by upregulating nuclear translocation of p65 NF-kappaB/RelA, Fas/FasL, caspase-3, DNA fragmentation, and apoptosis in Kupffer cells (all P < 0.001). Transfection with p65 siRNA attenuated the elastase-induced nuclear translocation of p65 NF-kappaB/RelA, upregulation of Fas/FasL, caspase-3, DNA fragmentation, and apoptosis in Kupffer cells (all P < 0.001). Acute pancreatitis activates p65 NF-kappaB/RelA and induces apoptosis of Kupffer cells. Inhibition of p65NF-kappaB/RelA attenuates elastase-induced upregulation of proapoptotic pathways and apoptosis in Kupffer cells. The ability of Kupffer cells to autoregulate their stress response by inducing self-apoptosis warrants further investigation.