Approximately 35 million people in the United States are 65 or older, accounting for about 12.4 percent of the total population with a projected rise to 20 percent in 2030. The increase in the elderly population has major ramifications for many facets of American life. The next several decades will demonstrate sizable increases in the proportion of older men and women without family support and with generally less income. Another factor is the accumulating evidence of psychoactive substance use by the elderly. The anticipated growth in the use of substances (licit and illicit) will affect the readiness and ability of the elderly to continue working in a drug-free environment. Alcohol and substance abuse constitute an estimated 10 percent of all cases treated by geriatric mental health facilities, and alcohol, mental health, and drug abuse problems typically are concomitant and interactive. The chapters in this report provide a detailed review of the demographic and clinical perspectives of the elderly and substance abuse, examine various risk factors associated with the use of licit and illicit substances, describe the examination of several data sources that can contribute to an understanding of substance abuse and aging, discuss modeling efforts and the analysis of extant data, array preliminary projections of the number of elderly needing substance abuse services during the 2020-2030 time period, and describe the implications of these projections for needed substance abuse services. The report underscores the expected change in the magnitude of the requirement for substance abuse treatment in future generations of older Americans. Complementing the accelerated aging and changing demographic profile of the U.S. population will be a new set of factors, including longer life span, increased per capita use of multiple prescription drugs, increased pressure to retain older people in the workforce, and the enhanced propensity of those entering their senior years to abuse both licit and illicit drugs. All these factors will have an impact on both the Nation’s substance abuse treatment and the greater health care system. For a more informed policy, there is a need for new approaches. Tables and figures