The validity of moral rules and principles becomes legally important in any case involving the application of law in which a judge (or any law-applying authority) is obligated to take into account moral rules, principles or standards. In the paper, this problem is analysed from the legal point of view in reference to such moral rules and principles that cannot be simultaneously classified as legal ones (or as legally valid). First, the concept of an original normative situation is introduced. Next, the three basic questions are clarified: the question of the meaning of validity statements, the question of the recognition (identification) of valid moral rules and principles and the question of the justification of validity. The possible development of a coherent juristic conception of the validity of moral rules and principles is outlined through indicating the possible jurisprudential answers to such questions. Finally, the methodological approach based on the adoption of a morally detached and impartial point of view is recommended for further research.