This article identifies a high-risk subgroup of Medicare beneficiaries in the Medicare Coordinated Care Demonstration for which 4 of the 11 participating programs significantly reduced hospitalizations, and the distinguishing features of those successful programs. Frequent in-person contact (in addition to telephone contact) by care coordinators with patients and their providers, robust medication management, and comprehensive transitional care when patients are hospitalized were among six features common to the four programs that reduced hospitalizations for high-risk beneficiaries. These features were generally missing from the demonstration programs that did not reduce hospitalizations. If combined with modest coordination fees and cost-effective delivery methods, these interventions could generate a net Medicare savings for high-cost beneficiaries, who represent 18 percent of all Medicare beneficiaries and account for 37 percent of Medicare costs.