To receive health care, patients with nonemergent problems must gain access to a complex, interdependent ambulatory care system currently structured around the conventional office appointment model. The system does not effectively accommodate diverse patient needs and preferences, contributing to both overuse and underuse of health care resources. A patient-centered access model would help patients secure appropriate and preferred medical assistance when and where it is needed. Characteristics of patient-centered access include availability, appropriateness, preference, and timeliness. One or more of these characteristics often is missing in patients' health care experiences. The goal of this paper is to present patient-centered access as an integrated concept and philosophy to provide context for evaluating specific access initiatives. On the basis of an assessment of existing literature, 3 organizing principles of patient-centered access are proposed and discussed: work at the high end of expertise; align care with need and preference; and serve when service is needed. Patient-centered access warrants serious consideration, given the stakes involved for patients, providers, and payers. Few concepts support all 6 of the Institute of Medicine's aims for the 21st century: safety, effectiveness, patient-centeredness, timeliness, efficiency, and equitability. Patient-centered access is such a concept.