Monokine induced by IFN-${gamma}$ (Mig) and IFN-${gamma}$-inducible protein of 10 kDa (IP-10) are strongly induced by IFN-${gamma}$ in a range of cell types, including monocytes, keratinocytes, endothelial cells, and astrocytes, but previous works have shown their patterns of expression differ according to stimulus. The purpose of this study was to compare the effect of lipopolysaccharide (LPS) on the expression of the inflammatory chemokine Mig with that of IP-10 gene in mouse peritoneal macrophages. Mig mRNA was, although expression of the gene was weak, detectable upon exposure to LPS. LPS-induced Mig mRNA expression was in a strain-specific fashion and independent upon the dose of LPS, but expression of LPS-induced IP-10 mRNA was dose dependent manner and higher than IFN-${gamma}$-induced IP-10 mRNA. The effect of LPS in induction of Mig mRNA occurred late, but the mRNA expression sustained evenly until prolonged time point. IL-12 synergized with LPS to induce the expression of Mig mRNA, but did not in the expression of IP-10 mRNA. The synergistic effect of IL-12 on LPS-induced Mig mRNA expression was dependent on new protein synthesis, and controlled at the transcriptional level. These data suggest that although IP-10 and Mig have similar effects and characteristics on inflammatory reactions, each of these two chemokines may have different mechanisms in the reaction with LPS.