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This study was conducted to determine if the p38 and ERK1/2 MAPK pathways are involved in transcription of IL-6, IL-8, and COX-2 in the chicken thrombocyte response to ligation of Toll-like receptor 4 (TLR4) by Salmonella minnesota lipopolysaccharide (LPS). Thrombocytes were isolated and subsequently treated with either p38 MAPK or ERK inhibitor, and then with LPS during in vitro cell culture. Transcription of IL-6, IL-8, and COX-2 mRNA was determined using real-time PCR. The experiments were repeated using pM, nM and μM concentrations of both inhibitors to test cell sensitivity. Stimulation with LPS induced expression of IL-6, IL-8 and COX-2 mRNA. This expression was reduced by treatment with 25 μM ERK inhibitor as well as by treatment with 70 μM p38 MAPK inhibitor. However, treatment with 25 pM and nM ERK inhibitor, and with 70 pM and nM p38 MAPK inhibitor, yielded no decrease in mRNA expression in relation to treatment with LPS alone. Inhibition with both the ERK and p38 MAPK inhibitors was in accordance with previously established concentrations for mammalian cells. It is now apparent that the p38 and ERK1/2 MAPK pathways are both linked to gene expression of a cytokine, a chemokine and an enzyme involved in the thrombocyte innate response to TLR4 ligation by bacterial LPS.