Social pension systems in most countries in Eastern Europe and the former Soviet Union face severe financial pressure. Aging populations are increasing that pressure, which stems mainly from in the%design in the %in the flaws and incompatible incentives in the systems. The authors describe the features of the ion systems that have led to the current dire predicament: a big discrepancy between system and demographic dependency ratios, unsustainable targeted replacement rates, the high contribution rates needed, growing evasion, and growing deficits. Radical basic reform is inevitable, they say, but may not be politically feasible or even advisable in the short run. After reviewing experience in other countries, they conclude that restructuring and downsizing the social ion system will leave adequate but affordable (thus sustainable) benefits and will allow for the creation and growth of private pension funds. The shortcomings of company-based defined benefit plans (limited portability, restricted vesting, inadequate funding) suggest that transitional economies should opt in the longer run for non-employer, defined contribution plans based on individual capitalization accounts with full immediate vesting, full portability, and full funding. To cope with the need for a targeted replacement rate, such schemes could operate with variable contribution rates, reset each year in accord with the salary growth of each worker, the cumulative investment return on his/her acount, and the targeted pension benefit. Once private pension funds are established, long-term financial resources should accumulate rapidly. They can then play a major role in modernizing securities markets, stimulating innovation, fostering better accounting and auditing standards, and promoting more disclosure of information. They could also greatly help improve corporate governance and the monitoring of corporate performance. Their"voice"in corporate affairs could be exercised more effectively through collective bodies. They could thus help create more robust structures of corporate governance, lower monitoring costs, and avoid the problems caused by"free riding".