While cultural competency is widely promoted, the lack of a measure of cultural competency limits our ability to evaluate interventions and to understand the effects of cultural competency on health care quality. Based on a conceptual framework of cultural competency derived from expert focus groups, we developed a patient-reported measure of physician culturally competent communication behaviors that we validated in a group of 429 adult primary-care patients with diabetes and/or hypertension and their 53 physicians. Construct validity was supported by a moderate association with both patient satisfaction (r = .32, p < .001) and patient trust (r = .53, p < .001). Predictive validity was supported by an association with a decrease in blood pressure among hypertensive patients (r = –.18; p < .05). This new measure may be useful in assessing levels of culturally competent provider behavior and investigating associations between provider cultural competency and health care processes and outcomes.