Culturally competent healthcare has emerged as a policy solution to racial and ethnic health disparities in the United States. Current research indicates that patient-centered care is a central component of culturally competent healthcare, and a rich literature exists on how to elicit patients' lifeworld voices through open-ended questions, sensitive communication skills, and power-sharing interaction styles. But it remains largely unclear how doctors create linkages between cultures of medicine and lifeworld as two sets of incongruent meaning systems. Without such linkages, a doctor lacks the cultural tool to incorporate her patient's assumptions or frameworks into the voice of medicine, rendering it difficult to (at least partially) expand and transform the latter from within. This study explores how doctors perform this bridging work, conceptualized as cultural brokerage, on the job. Cultural brokerage entails mutual inclusion of different sets of schemas or frameworks with which people organize their meanings and information. Based on 24 in-depth interviews with primary care physicians in Northern California, this study inductively documents four empirical mechanisms of cultural brokerage: 'translating between health systems', 'bridging divergent images of medicine', 'establishing long-term relationships', and 'working with patients' relational networks'. Furthermore, the study argues that cultural brokerage must be understood as concrete 'cultural labor', which involves specific tasks and requires time and resources. I argue that the performance of cultural brokerage work is embedded in the institutional contexts of the clinic and therefore faces two macro-level constraints: the cultural ideology and the political economy of the American healthcare system.