Aging is characterized by the interlocking decay of biological functions over time. Microarrays have been successful in elucidating some of the genome-wide changes that occur with age. Using the AGEMAP dataset that catalogs changes in gene expression as a function of age in 16 tissues in mice, we identified tissue-specific aging genes. Coordinated aging processes across different tissues then were clarified in crosstissue coexpression networks on both the gene and pathway levels. Our findings provide more concrete information about coordinated aging across different tissues. By bridging gene-level and tissue-level research, this study could help identify targets for attenuation of critical aging-related genes, pathways, or networks for antiaging intervention.