The contribution of developing a theory from this standard of care is that it can express a new unifying idea about the phenomenon of peaceful end of life for terminally ill patients. It allows for generating and testing hypotheses that can provide new insights into the nature of this phenomenon and can contribute to increased knowledge about nursing interventions that help patients toward a peaceful end of life. The process of theory development from standards of care as described in this article also can be applied to other phenomena. Clinical practice abounds with opportunities for theory development, yet nurses often do not use theories to guide their practice. Until now, little guidance has been provided to tap the richness of clinical knowledge for the development of middle-range theories. Whereas the method described in this article may still be further refined, it offers a promising approach for the development of theories that are applicable to practice and move beyond the scope of grand theories. Thus deriving theories from standards of care can offer an important contribution to the development of the discipline's scientific knowledge base and enhanced practice.