In this study, we examined gene expression changes in the cortex and the medulla of the kidney from 74 patients of diverse age using Affymetrix DNA chips. We found 985 genes that change their abundance in the kidney with age. Some of the genes that increase in abundance with age are known to be specifically expressed in immune cells, suggesting that immune surveillance or inflammation increases with age. Almost all of the age-regulated genes show a similar aging profile in the cortex and the medulla, and are expressed broadly throughout development. These results suggest that the cortex and the medulla may share a common underlying mechanism for aging. The set of aging-regulated kidney genes suggest specific mechanisms and pathways that may play a role in kidney degeneration with age.