Although primary care is fundamental to health system performance, the United States has undervalued and underinvested in primary care for decades. This brief describes how the Affordable Care Act will begin to address the neglect of America's primary care system and, wherever possible, estimates the potential impact these efforts will have on patients, providers, and payers. The health reform law includes numerous provisions for improving primary care: temporary increases in Medicare and Medicaid payments to primary care providers; support for innovation in the delivery of care, with an emphasis on achieving better health outcomes and patient care experiences; enhanced support of primary care providers; and investment in the continued development of the primary care workforce.