Objectives : Citrus is the fruit that is readily available around us. Therefore, we investigated the anti-inflammatory effects of fraction isolated from the Citrus hassaku pericarp in RAW264.7 macrophage cells. Methods : The effects of fraction from Citrus hassaku pericarp on cell viability on RAW264.7 cells were measured by the MTT assay. The mRNA levels of iNOS and COX-2, its protein level by fraction of Citrus hassaku pericarp treatment in RAW264.7 macrophage cells were investigated by RT-PCR and immunoblots. Nitrite accumulation in the culture was measured colorimetrically by the Griess reaction using a Griess reagent. The amount of IL-6 and TNF-${alpha}$ production was determined using an enzyme-linked immunosorbent assay (ELISA) kit. Results : The results indicated that the fraction of Citrus hassaku pericarp concentration highly suppressed lipopolysaccharide (LPS)-induced nitric oxide (NO) and IL-6 productions without a cytotoxic effect on RAW264.7 cells. fraction of Citrus hassaku pericarp inhibited the expressions of LPS-induced iNOS and COX-2 protein and their mRNA in a dose-dependent manner. Particularly, fraction of Citrus hassaku pericarp suppressed the level of nuclear factor-${kappa}B$ (NF-${kappa}B$) activity, which was linked with the suppression of LPS-induced phosphorylation of p65 at serine 276 and p65 translocation into nuclei, but not MAPK signaling. In addition, treatment with fraction of Citrus hassaku pericarp inhibited the production of IL-6 and TNF-${alpha}$ in LPS-stimulated RAW264.7 cells. Conclusion : Our results indicate that fraction of Citrus hassaku pericarp potentially inhibits the biomarkers related to inflammation through the blocking of NF-${kappa}B$ p65 activation, and it may be a potential therapeutic candidate for the treatment of inflammatory diseases.