Surfactin is a natural biosurfactant derived from Bacillus subtilis and has various biological activities such as anticancer, antiplatelet, and anti-inflammatory effects. In this study, the inhibitory mechanism of surfactin in NO production from macrophages was examined. Surfactin down regulated LPS-induced NO production in RAW264.7 cells and primary macrophages with $IC_{50}$ values of 31.6 and $22.4{mu}M$, respectively. Immunoblotting analysis showed that surfactin strongly blocked the phosphorylation of IKK and $l{kappa}B{alpha}$ and the nuclear translocation of $NF-{kappa}B$ (p65). Therefore, these data suggest that surfactin may act as a bacterium-derived anti-inflammatory agent with anti-$NF-{kappa}B$ activity.