The healthcare reform debate has focused heavily on establishing Accountable Care Organizations (ACOs). ACOs are designed to be provider-based organizations focused on improving quality while reducing (or slowing) spending. If such quality and cost benchmarks are met, the ACO receives shared savings from payers. This type of approach has been implemented in programs such as the Medicare Physician Group Practice Demonstration. The ACO approach incorporates steps such as wellness programs, coordination of care, disease management, and other programs that focus on outcomes. The key features are local accountability, shared savings, and performance measurement. An ACO can encompass a wide variety of potential provider collaborations; however the unifying theme is accountability for overall care and efficiency. Current examples are integrated delivery systems, physician-hospital organizations, or physician networks. However, pending final healthcare reform legislation, certain design elements will be important to consider. For example, the form, scope and governance of the entity will need to be well defined. Similarly, investment in infrastructure, technology and data will be critical to capture and report on quality and efficiency measures. ACOs are receiving significant attention in the healthcare reform debate and are a likely model to be adopted.