With the prohibitive and rising cost of healthcare, there has never been a greater need for accountable care organizations, according to Mark McClellan, MD, former administrator for the Centers for Medicare and Medicaid Services. McClellan's comments came at the National Health IT and Delivery System Transformation Summit, held in conjunction with Second Annual National Accountable Care Organization Summit June 27 and 28 in Washington, DC. The challenge of achieving better care at lower costs has never been more important or more urgent, he said, and the serious challenges of getting from here to there have never been more daunting. McClellan, who is now the director of the Engelberg Center for Health Care Reform at the Brookings Institution, said in the past year the Centers for Medicare and Medicaid Services has identified many of the challenges faced by providers when starting an ACO, and there are now some successful ACOs from which to draw experience. "ACOs are about fundamental changes," he said. "The main emphasis is to get away from fee-for-service payment structures."