Empirical realities and technological advances in the clinical practice context continuously call for ethical dialogue among healthcare providers. The nurse's voice of advocacy for humane caring grounded in an existential understanding of the complexities of the health experience remains a salient responsibility of moral agency. If nurses are to care for families, as society requires, then nurse caring, a phenomenon currently defined and understood primarily at the individual patient-nurse level, must be diligently and broadly explored in terms of its worth to guide nursing service with families. The purpose of this theoretical paper is to explore a conceptualization of care with families in the health experience that emanates from the philosophical tenets of existentialism and underpinnings of symbolic interactionism and is interpreted into action by the ethics of care. Current and classic literature, inclusive of philosophical and empirical works, provide the background for analysis of the following elements: existential caring orientation, family perspective, family-nurse interaction, construction of meaning, family meaning construction, nurse meaning construction, family-nurse co-construction of meaning and existential advocacy. Existential philosophy is understood as the basic underlying lens guiding the nurse in taking an existential caring orientation as depicted in the resultant conceptualization. Caring in the family health experience is best facilitated by a relational stance where the nurse acknowledges the family's unique perspective. Through the family-nurse interaction the nurse gains understanding of the family's perspective being constructed. Nursing practice with families confronting the empirical realities and technological advances of the new millennium will be enriched when moral agency includes ethical dialogue among healthcare providers and families. Existential advocacy with and for families grounded in the nurse's understanding of the family perspective enhances the context for moral agency.