Quercus salicina has been widely used as a traditional medicine for the treatment of various diseases. In macrophages, nitric oxide (NO) is released as an inflammatory mediator and has been proposed to be an important modulator of many pathophysiological conditions in inflammation. In the present study, the inhibitory effect of methanolic extracts of Q. salicina (QSM) on NO production in LPS-stimulated mouse (C57BL/6) peritoneal macrophages was investigated. QSM suppressed NO production without notable cytotoxiciy. QSM also exhibited down-regulation of inducible nitric oxide synthase (iNOS) and cyclooxygenase-2 (COX-2) expression via attenuation of NF-${kappa}B$ translocation to nucleus in rIFN-${gamma}$ and LPS stimulated mouse peritoneal macrophages. The present study strongly suggest that Q. salicina may be beneficial in diseases which related to macrophage-mediated inflammatory disorders.