The term responsibility in a general form is initially defined in this paper following of an analyse to the nurse's civil, penal and ethics responsibilities regard of actual legislation. In a second part, the author identifies the commom problems that can occur of an inaccurate practice of the assistencial actions and the nurse's implications and their level of responsibility in relation to the severity of the deriving risk. At last, advise to the nurses to keep up atualized concerning to the scientific knowledge evolution and to the ethics and legal aspects of profession.