Intestinal epithelial cells are known to up-regulate the expression of several chemokines in response to bacterial toxins. Since there has been little understanding on the cellular mechanisms of C. difficile toxin A-induced mucosal inflammation, we investigated whether nuclear factor-kappa B $(NF-{kappa}B)$ could regulate chemokine gene expression in HT-29 intestinal epithelial cells stimulated with C. difficile toxin A. C, difficile toxin A rapidly increased signals of $NF-{kappa}B$ composed with p65 and p50 subunits in HT-29 cells, whereas it decreased the signals of $I{kappa}B{alpha}$. Blocking the $NF-{kappa}B$ activation by transfection with dominant negative $I{kappa}B{alpha}-containing$ retrovirus attenuated the upregulated expression of IL-8, $GRO-{alpha}$, and MCP-1 induced by C. difficile toxin A. These results suggest that $NF-{kappa}B$ is a major regulator of chemokine gene expression in C. difficile toxin A-stimulated Intestinal epithelial cells.