Insomnia affects approximately one-third of older Americans. More than half of all people aged 65 and older experience sleep problems. The prevalence of insomnia and other sleep disorders is not a natural part of aging but is high in older adults because of a variety of factors common in late life. One of those factors may be a deficient magnesium status. There is a close association between sleep architecture, especially slow wave sleep, and activity in the glutamatergic and gamma-aminobutyric acid (GABA) system. Because magnesium is a natural N-methyl-D-aspartate (NMDA)antagonist and GABA agonist, magnesium apparently plays a key role in the regulation of sleep. Such a role is supported by supplementation, correlation, and animal studies showing that magnesium intake or status affects sleep organization.