Trust is a fundamentally important aspect of medical treatment relationships. Studies have established that patient trust predicts instrumental variables such as use of preventive services, adherence, and continued enrollment at least as well as satisfaction does, and is more salient for measuring the quality of ongoing relationships. Measuring trust would help to inform public policy deliberations and balance market forces that threaten the doctor-patient relationship. Several validated measures could be easily included in surveys. While further studies to evaluate the cost-effectiveness of measuring trust and test interventions to improve trust are desirable, the action merits serious consideration.