Development of genomics and bioinformatics enable us to analyze the global gene expression profiles of cells by DNA microarray. Changes in gene expression patterns indicate changes in its physiological conditions. Following the exposure of an organism or cell to toxic chemicals or other environmental stresses, the global genetic responses can be expeditiously and easily analyzed. Baker's yeast, Saccharomyces cerevisiae, is one of the most studied and useful model eukaryotes. The biggest advantage of yeast genomics is the available functional information for each gene and a considerable number of data are accumulating in the field of toxicity assessment using yeast DNA microarray. In this review, we discuss the toxicogenomics of metal ions, alcohols and aldehydes, and other chemicals. (C) 2010, The Society for Biotechnology, Japan. All rights reserved.