Objective To determine the role of the NF-kappaB/I-kappaB pathway during ischemia reperfusion (I/R) injury to rat liver. Methords A group of rats underwent partial hepatic ischemia and reperfusion. The left and median lobe of the liver was subjected to ischemia for 90 minutes followed by reperfusion for previously specified periods. NF-kappaB activity was analyzed by electrophoretic mobility shift assay (EMSA). The protein level of I-kappaB was assessed using West blot analysis. A semiquantitative reverse transcriptase polymerase chain reaction was used to analyze TNF-α and ICAM-1 mRNA levels. Results During liver I/R injury,NF-kappaB activation was induced in a time-dependent fashion. NF-kappaB was activated within 1 hour and 2 hours after the initiation of reperfusion and decreased afer 4 hours. The I-kappaB protein level was decreased in the cytoplasm after 2 hours, and the messenger RNA expression of TNF-α and ICAM-1 were increased simultaneously. Conclusions The data suggest that I-kappaB protein was degraded during hepatic I/R injury, NF kappaB was realeased and bound to special sequence in the promoters of budget genes, which regulated the expression of TNF-α and ICAM-1 mRNA. This provides evidence that the NF-kappaB/I-kappaB pathway plays an important modulating role in the expression of proinflammatory genes relevant to the development of ischemia reperfusion injury.