Within the discipline of family medicine, providing family care receives varying emphasis. Studies are needed to more strongly link the process of family care to improvements in health outcomes. Such studies require validated measures with which to quantify the amount of care provided to families. This paper proposes a conceptual definition and an operational quantitative measure of family care. This family care measure, which we based on a three-dimensional operational model of family care (frequency of visits, number of family members, number of providers), translates a family's pattern of health care into an easily interpreted index.