Social Security is the largest source of income for most older Americans and is even more vital to particular demographic subgroups of older Americans. Analyzing the Current Population Survey Annual Social and Economic Supplement (ASEC) for calendar year 2011, this briefing paper examines the role of Social Security and other income sources in the retirement security of older Americans. It explores the unique value of Social Security to different gender, age, race/ethnic, and marital groups. It finds that significant shares of the older population rely on Social Security for the majority of their income and that Social Security lifts 14.8 million people out of poverty.