The link between lower income and poorer health is well established. Lower income is known to be associated with lower life expectancy and higher rates of heart disease, cancer, and mental illness. 1 Access to health care is also known to be poorer for people with lower incomes. Primary care is frequently the point of first contact between healthcare services and individuals with health and social problems. Yet, income data is not routinely collected in primary care. Knowledge of patients’ income is consequently not incorporated into the clinical care of individuals, and is underutilised in policy making and healthcare planning for populations. Income interacts with behaviour, actions, and environment to impact health across the life course and across all sections of society. Evidencing, understanding, and acknowledging these interactions is essential if we are to tackle inequities in health. Should doctors in primary care record their patients’ income? We argue that it would bring individual and population benefits; that acceptability and practical applicability may be less problematic than first supposed; that a precedent exists in the routine collection of other sociodemographic data; and that the UK is lagging behind other countries in considering this issue.