Biochanin A, one of the major isoflavonoids in red clover or cabbage, has been reported to have anti-inflammatory effects. However, the molecular mechanism underlying the anti-inflammatory effects of biochanin A has not been completely elucidated. The aim of this study was to investigate the anti-inflammatory effect and mechanism on lipopolysaccharide (LPS)-stimulated BV2 microglia. The results showed that biochanin A suppressed LPS-induced inflammatory mediators nitric oxide, prostaglandin E2 and inflammatory cytokines TNF-α and IL-1β production. LPS-induced NF-κB activation was also inhibited by biochanin A. In addition, biochanin A up-regulated the expression of PPAR-γ and the anti-inflammatory effects of biochanin A can be abolished by PPAR-γ antagonist GW9662. These results suggest that biochanin A exerts an anti-inflammatory property by activating PPAR-γ, thereby attenuating NF-κB activation and the release of pro-inflammatory mediators.