Abstract: Objective To investigate the clinical significance of alteration in factors associated with Toll-like receptor signaling pathway in infants with sepsis. Methods Twenty infants with sepsis (sepsis group) and another 20 with severe septic shock and multi-organ dysfunction syndrome (severe sepsis group) admitted to Duanzhou Women and Children Hospital in Zhaoqing and Guangzhou Women and Children Hospital between June 2009 and March 2011 were included in this study. A contemporary cohort of 20 healthy infants were set as control group. The expression of Toll- like receptor2 (TLR2) and receptor4 (TLR4) on peripheral blood mononuclear cells (PBMC) was examined with flow cytometry, and the plasma levels of tumor necrotizing factor alpha (TNF-α) and IL-6 with ELISA. Results The sepsis group and severe sepsis group showed significantly higher positive rates of TLR2 and TLR4 expression on PBMCs as compared with the control group[(52.48±27.37)% and (80.56±42.95)% vs (15.63±9.28)%; (26.58±14.26)% and (49.32±23.74)% vs (2.84±2.07)%; all P<0.01]. The levels of TLR2 and TLR4 expression on PBMC were higher in severe sepsis group than those in sepsis group (P<0.01). Compared with control group,the plasma pro-inflammatory cytokines TNF-α and IL-6 were significantly elevated in sepsis group and even higher in the severe sepsis group (P<0.01). Conclusion In infants with sepsis, TLR2 and TLR4 may be involved in the pathogenic microbes and activation of TLR signaling pathway, and may also mediate production and release of serum pro-inflammatory factors, such as TNF-α and IL- 6.