This study is part of the theoretical referential of doctorate in development thesis based on Bertalanffy, Vasconcellos and Capra's ideas. It searches from the systemic approach to comprehend the family as a inter-relations system among the members, an irreducible open unit to the continuous flow of entrance and exit of energy, a dynamic unit in which the whole and the parts are influenced mutually. It aims the development of a professional reflection for the Care of Nursing for the family not as context, but the familiar one. Its genesis is related to the many concerns that have surfaced from professional activities which have met answers in the new paradigmatic approach of the post-modern science of the complexity, instability, intersubjectiveness for the think/act of Nursing in the interdisciplinary development of their careful actions of joint way: the unit family.