We estimated the effects of three Health Care Financing Administration (HCFA)-funded case management demonstrations for high-cost Medicare beneficiaries in the fee-for-service (FFS) sector. Participating beneficiaries were randomly assigned to receive case management plus regular Medicare benefits or regular benefits only. None of the demonstrations improved self-care or health or reduced Medicare spending. Despite the lack of effects of these interventions, case management might be cost-effective if it includes greater involvement of physicians, is more well-defined and goal-oriented, and incorporates financial incentives to generate savings in Medicare costs. Models incorporating these changes should be investigated before abandoning Medicare case management interventions.