The changes of Toll-like receptor (TLR) 2, 4 of peripheral blood mononuclear cells (PBMCs) in the acute abdomen patients associated with systemic inflammatory response syndrome (SIRS) and their potential significance were explored. A clinical study was performed on 103 acute abdomen patients in whom 65 were associated with SIRS. Forty healthy individuals served as normal controls. The mRNA expression of TLR2, 4 was detected by RT-PCR, and the expression of TNF-αand IL-6 by ELISA. The level of plasma endotoxin, hospital stay and mortality were measured. It was found that the endotoxin level was increased to varying degrees in all the acute abdomen patients, and the endotoxin level was and hospital stay longer in SIRS group than in non-SIRS group (P＜0.01).TLR2 mRNA, TLR4 mRNA, IL-6 and TNF-α could be detected with low value in normal controls,but they were up-regulated markedly on the 1 st day after admission. Then TLR4 mRNA, IL-6 and TNF-α were decreased gradually, but TLR2 mRNA maintained at a high level till the 5th day. These indexes above in SIRS group were higher than those in non-SIRS group (P＜0.01). The results of correlation analysis revealed the expression of TLR2, 4 mRNA was positively correlated with the levels of TNF-α and IL-6, and the hospital stay. The results of Logistic regression demonstrated that overexpression of TLR2, 4 mRNA might result in higher risk of multiple organ dysfunction syndrome (MODS). It was concluded that in the acute abdomen patients associated with SIRS, the expression of TLR2, 4 in PBMCs was increased markedly, suggesting that TLR might play an important role in the pathogenesis of acute abdomen associated with SIRS.