We present a detailed characterization of the chitin oligosaccharide elicitor-induced gene OsWRKY53. OsWRKY53 was also induced in suspension-cultured rice cells by a fungal cerebroside elicitor and in rice plants by infection with the blast fungus Magnaporthe grisea. A fusion of OsWRKY53 with green fluorescent protein was detected exclusively in the nuclei of onion epidermal cells, and OsWRKY53 protein specifically bound to W-box elements. A transient assay using the particle bombardment method showed that OsWRKY53 is a transcriptional activator. A microarray analysis revealed that several defense-related genes, including pathogenesis-related protein genes such as PBZ1, were upregulated in rice cells overexpressing OsWRKY53. Finally, overexpression of OsWRKY53 in rice plants resulted in enhanced resistance to M. grisea. These results strongly suggest that OsWRKY53 is a transcription factor that plays important roles in elicitor-induced defense signaling pathways in rice.