Up-regulation of cell adhesion molecules and pro-inflammatory cytokines contributes to enhanced monocyte adhesiveness and infiltration into the skin, during the pathogenesis of various inflammatory skin diseases, including atopic dermatitis. In this study, we examined the anti-inflammatory effects of butein, a tetrahydroxychalcone, and its action mechanisms using TNF-α-stimulated keratinocytes. Butein significantly inhibited TNF-α-induced ICAM-I expression and monocyte adhesion in human keratinocyte cell line HaCaT. Butein also decreased TNF-α-induced pro-inflammatory mediators, such as IL-6, IP-10 and MCP-1, in HaCaT cells. Butein decreased TNF-α-induced ROS generation in a dose-dependent manner in HaCaT cells. In addition, treatment of HaCaT cells with butein suppressed TNF-α-induced MAPK activation. Furthermore, butein suppressed TNF-α-induced NF-kappaB activation. Overall, our results indicate that butein has immunomodulatory activities by inhibiting expression of pro-inflammatory mediators in keratinocytes. Therefore, butein may be used as a therapeutic agent for the treatment of inflammatory skin diseases.