Informing the patient about his disease is a very important issue in the medical practice, thus communication becomes imperative in healthcare services. Communicating the diagnosis of a pathology that doesn't bear any imminent risk for life is a common procedure for physicians. However, the situation changes drastically in the case of a severe diagnosis or a hopeless prognosis, with terminally ill patients.In this article the authors proceed to a critical analysis of the dilemma of communication or non-communication of a severe diagnosis.The problem of communicating a severe diagnosis is described from a philosophical perspective (in terms of three fundamental ethical theories: Aristotle's theory of virtue, Kant's ethical theory and Bentham and Mill's moral theories). At the same time, certain physiological and medical approaches are presented.In order to avoid any communication conflict, especially considering the particular situation of the seriously ill patient in the context of the contemporary medical activities, the authors propose the debating of two opposing approaches: "the sacred lie principle" and "the justified medical truth" in the physician--patient relation.