This article will be concerned with the phenomenon of vitality, which emerged as one of the main findings in a larger grounded theory study about life and death decisions in hospitals' neonatal units. Definite signs showing the new-born infant's energy and vigour contributed to the clinician's judgements about life expectancy and the continuation or termination of medical treatment. In this paper we will discuss the normative importance of vitality as a diagnostic cue and will argue that vitality, as a sign perceived by doctors and nurses, has moral significance and represents a legitimate contribution to clinical decision-making in difficult cases where the child's life is at stake. We will argue that these clinical intuitions can be justified on a moral basis but only with certain qualifications that accounts for a certain objectivity and intersubjective reliability in the therapeutic judgements.