Recent studies of the brassinosteroid-deficient mutants have revealed that brassinosteroid plays essential roles to control plant growth and development, such as cell elongation, division and photomorphogenesis. However, its regulatory mechanisms and signal transduction pathway are still under unclear. We performed DNA microarray analysis (Gene Chip, Affymetrix) to analyze BR-regulated genes comprehensively. The known BR-regulated gene, TCH4 gene that encodes xylogucan (endotransglycosylase) XET was hightly induced by BR treatment. The expression of genes, which involved in BR biosynthesis, such as CPD, were repressed by BR treatment. Novel BR-regulated genes were also found.