Pensions are an important and increasingly common supplement to Social Security benefits for persons aged 65 or older--particularly for those in the the middle and upper income quintiles. By 1990, pension income was reported by 44 percent of all elderly units--57 percent of the couples and 34 percent of unmarried persons. This article discusses the role of pensions in the income of the elderly; private pension coverage, vesting, and types of plans among active workers; how the shift toward defined contribution plans poses new problems in assessing the role of private pensions in providing retirement income security; and expected pension receipt rates for the future elderly. Pension receipt among the elderly is expected to continue to grow over the next 20-30 years because of past growth in coverage and vesting. Microsimulation models are a relatively new tool for forecasting the future distribution of pension income. The models offer a framework for considering the research questions that, if answered, would help improve our understanding of the impact of the pension system on future income security.