In this paper, we try to expose the fundamental ideas at the basis of Jorge Millas' axiology. First, we will expose synoptically the core of the legal philosophy that the Chilean thinker develops on his works on the subject, including his conception about philosophy in general 01), and about legal science in particular (2). Secondly, we will expose the epistemological suppositions of his legal philosophy (3), and his consequent conception of law's essence (4), the legal rule (5) and its foundation, and the axiological theory that Millas develops on the basis of the distinction and relationship between "is" and "ought" (6). We conclude with a critical analysis that pretends to expose the strengths and weaknesses of the legal theory of this Chilean author ( 7 and 8).