The present article attempts to determine whether culpability, commonly considered a principle of criminal law, actually meets the characteristics of a norm as a principle in the light of the German legal theorist R. Alexy’s theory of legal principles, or perhaps it is a norm as a rule. At the outset, the author hypothesises that the norm embodied in Article 1(3) of the Criminal Code is indeed a legal principle. Then, he presents Alexy’s aforementioned theory in detail and goes on to discuss the concept of culpability. Advocating the comprehensive normative theory, he defines culpability and indicates its necessary elements – the psychological one and the normative one. In the further part, he presents two selected cases in which the so-called fiction of culpability is adopted (criminal liability in the case of unconscious unintentionality, i.e. negligence, and the situation described in Article 31(3) of the Criminal Code). They confirm the hypothesis put forward and, at the same time, make it clear that the norm provided for in Article 1(3) of the Criminal Code is indeed a principle as understood by R. Alexy.