The paper focuses on issues of development dimensions of Medical Law and its ongoing process of standardization and harmonization on one hand, versus the traditionally rooted and available principles of biomedical ethics, on the other. The collision of new legal institutes and the spread of human rights protections is evident. This paper follows the theory and practice of medical ethics and medical law. The theoretical aspect points out medical ethics as one of the sources of medical law. Legal theory makes a distinction between formal and autonomous sources of medical law. Even though ethics is morally much higher, law prevails because it has stronger sanctions and legal power. In its practical aspect, this paper gives examples of different situations of medical decision-making processes. Ethical rules are of the utmost relevance in the domain of confidentiality and options of medical treatment. But, in concrete medical procedures, where legal positions of patients are evidently very significant, law has a more distinct function. Therefore, explaining particular cases from medical malpractice, such as cases of penal, civil or professional liability have an ethical dimension as well. Members of medical professions in Serbia often find these cases unfair. Mostly this is the consequence of ignorance in this kind of medical law and ethics relations. A discussion about practical cases has in that sense a self-learning component, which could be developed to strengthen ethical reasoning and judgment.