Despite many important efforts to increase equity in the US health care system, not all Americans have equal access to health care—or similar health outcomes. With the goal of lowering costs and increasing accessibility to health care, the nation's new health care reform legislation includes certain provisions that expand health insurance coverage to uninsured and underinsured populations, promote medical homes, and support coordination of care. These provisions may help narrow existing health care disparities. Many of the most vulnerable patients, however, may continue to have difficulty accessing and navigating the complex US health care delivery system. This article explores the unique role that patient navigation can play in improving health outcomes for racial and ethnic minorities, as well as other underserved populations, in the context of a changing healthcare environment. Patient navigators can not only facilitate improved health care access and quality for underserved populations through advocacy and care coordination, but they can also address deep-rooted issues related to distrust in providers and the health system that often lead to avoidance of health problems and non-compliance with treatment recommendations. By addressing many of the disparities associated with language and cultural differences and barriers, patient navigators can foster trust and empowerment within the communities they serve. Specific patient navigator activities are discussed, and metrics to evaluate program efforts are presented. Cancer 2011;117(15 suppl):3541–50. © 2011 American Cancer Society.