This study examined the effects of omega-3 polyunsaturated fatty acid (omega-3PUFA) on the expression of toll-like receptor 2 (TLR2), toll-like receptor 4 (TLR4) and some related inflammatory factors in peripheral blood mononuclear cells (PBMCs) of patients with early-stage severe multiple trauma. Thirty-two patients who were admitted to the Department of Traumatic Surgery, Tongji Hospital (Wuhan, China) between May 2010 and November 2010, and diagnosed as having severe multiple trauma with a injury severity score (ISS) no less than 16, were enrolled in the study and divided into two groups at random (n=16 in each): omega-3PUFA group and control group in which routine parenteral nutrition supplemented with omega-3PUFA or not was administered to the patients in two groups for consecutive 7 days. Peripheral blood from these patients was collected within 2 h of admission (day 0), and 1, 3, 5 and 7 days after the nutritional support. PBMCs were isolated and used for detection of the mRNA and protein expression of TLR2 and TLR4 by using real-time PCR and flow cytometry respectively, the levels of NF-kappa B by quantum dots-based immunofluorescence assay, the levels of TNF-alpha, IL-2, IL-6 and COX-2 by ELISA, respectively. The results showed that the mRNA and protein expression of TLR2 and TLR4 in PBMCs was significantly lower in omega-3PUFA group than in control group 5 and 7 days after nutrition support (both P < 0.05). The levels of TNF-alpha, IL-2, IL-6 and COX-2 were found to be substantially decreased in PBMCs in omega-3PUFA group as compared with control group at 5th and 7th day (P < 0.05 for all). It was concluded that omega-3PUFA can remarkably decrease the expression of TLR2, TLR4 and some related inflammatory factors in NF-kappa B signaling pathway in PBMCs of patients with severe multiple trauma, which suggests that omega-3PUFA may suppress the excessive inflammatory response meditated by the TLRs/NF-kappa B signaling pathway.