The advance of genomics has led to the definition of thousands of human genes as well as the identification of a significant proportion of genes in non-human organisms. We are utilizing these advanced genomic resources coupled with modern engineering and informatics capabilities to establish and maintain a state-of-the-art cDNA microarray center laboratory. The mission of the NIEHS Intramural Microarray Center (NMC) is to develop a research program in the Division of Intramural Research at the NIEHS that utilizes the advances in genomics to address critical threats to human health as a consequence of environmental exposures, specifically incorporating genome-wide gene expression analysis using microarray technology, with the goal of reducing or eliminating these threats to human health. In order to accomplish this mission, the goals of the NMC include: 1) the pursuit of mechanistic investigations of the impact of exposures on gene expression and alterations in critical cellular regulatory pathways, 2) the utilization of global gene expression changes following environmental stresses to identify specific changes, using bioinformatics tools, that are tightly linked with a deleterious human health outcome as patterns or biomarkers of a particular disease or toxic outcome, and 3) the continual development of new and better approaches to address genome-wide changes in gene expression. One consequence of this research program will be the accumulation of global gene expression information that will contribute to the population of an environmental health and toxicogenomics gene expression database. Such a public database will allow scientists to better understand the mechanism of action of environmental agents on human health and better evaluate the consequences associated with such exposures prior to the appearance of pathological presentation. This information may allow for the intervention and prevention of disease outcomes.