This paper aims answering the following question: is it possible a Philosophy of Law starting from the use of concepts, methods and Michel Foucault s philosophy? That is, this question is not identical to that which searches in the French philosopher s path, the transformed group of his formulations, statements and enunciation of problems related to Law. Those who know him are aware of the importance of this object in Foucault s philosophical concerns. Thus, betting on this statement, I focused my efforts in the sense of determining the specific form to be given to what I called, at least temporarily, new philosophy of Law, whose distance towards the instituted philosophies of Law would be equivalent to those seen between archeology and genealogy relatively to the group of academic philosophies. Admitting this initial hypothesis, it was necessary to define archeology and genealogy as critical interpretation instruments (abstracting me from the whole problem involving the relationships of this specific method of Focault, elaborated to fit the discourses of human sciences, as hermeneutics in general and its philosophical postulates) and transformation of historical and political reality (and of ourselves),since the its use from which we are legitimated to do in the field of the construction of na other philosophy of Law is linked to the guidelines highlighted by Foucault in his historical trials. How could we make Nietzshe s postulates worth by the autor of Les Mots et les Choses, Surveiller et Punir, Volonté de savoir takin as reference the group of discourses, procedures and juridical practices inside the formationof specific histories which the archeologist and genealogist must cut out and describe? Other philosophy of Law erected in opposition to a Philosophy of the Rule of Law; a pragmatic thought, critically guided (searching for the a priori of knowledge and action) by history, whose post-modern characteristic lies in refusing any kind of transcendental anthopologism, and whose objectives is the functioning description of juridical practices without considering the historical universals, only if it is to denounce and expose them. The contrary, however, of a critic which presupposes the transcendence of those historical universals in their inner selves, prisoner of a permanent tension between the subject s transcendental structures and its empiric forms of existing, that is, what Foucault called anthropologic sleep, our new dogmatic sleep. Thus, I strategically took chance of a text that has become central for the development of the hypothesis of this Master s degree dissertation. In Qu est-ce que les Lumières?, Focault attempts to insert his critical thought, the specific type of historical critic that he aimes to develop, regarding the group of modern philosophies which tried, in different ways, to answer to Kant s issue introduced in 1784 by a German newspaper, the Berlinische Monnatsschrift: was ist Aufklarung? The line of thought which he describes as constituting the type of critic that he proposes to abandon is just the same as Habermas. When defining it as a philosophical ethos, na ontology of ourselves, Foucault points out the need of turning Kant s critic traditionally anthropologic, whose limits are negative, into a historical genealogical critic of the individual who assumes himself a positive attitude about historically configured limits which determines us as subjects of what we think, say and do; na addresses critic, therefore, to possibly exceed these historically arbitrary limits. It could be said that this paper is essentially a work of methods, methodological planning of a line of though which seeks production, adapting new concepts to this new philosophy of Law that it is not only supposed to be possible, but could truly be found in classes, lectures, interviews, in the works of a French historian. It is in this sense that the name critic mus be understood, fundamental for a fully comprehension of the accomplished work: Simultaneously, it involves questions regarding methodological constructions, the guidance that should be given to Philosophy nowadays, the relationship that mus be established with scientific knowledge, the human science, the simultaneously ethical and political role of the inttellectual-philosopher, its insertation in historic experience of present time, its ontological conception of Reason, etc. It had been fundamental for the establishment not of a comparison, but of na opposition which allowed me to better visualize the Foucault s critical specificity, placing him in a characterizes habermasian communicative Reason understood as a correction of instrumental reason. Actually, both Foucault and Frankfurt s School, and Habermas, in particular, recognize the existence of fundamental historical ties of Contemporary philosophy with Enlightment, whose comprehension determines the way philosophy accomplishes its aim in diagnosing the society, the present. In an hermeneutic language, it could be said that critic worked as na interpretation key of these two pholosophical bets, taking advantage of relation that both establish between this name and the group of its respective trials, having as an objective to better in its own specificity, in its specific instrumentality about this other philosophy of Law, as well as it does about other forms of contemporary philosophy. This Master s degree dissertation attempted, therefore, explicit its methodological suppositions (what kind of juridical methodology can we bild up starting from Foucault s legacy?). It was on this sense that I got appropriated of that literature around Habermas-Foucault debate, linking, in a maybe little arbitrary way, the transformation of critic in the opposition established between the two forms of thinking. Both Foucault and Habermas (the latter in na explicit manner) offer different possibilities for us to work in the field of philosophy of Law; these possibilities are not only in specific works but also, they meet in the entire accomplished work as a whole. Taking chance of that position, refusing habermasian approach inside this opposition itself, I considered both archeology and genealogy as methodological tools, critics and specific historic of such foucaultian philosophy of Law. Archeology as form of critical relationship with the speeches of the science of the Right, with the statements of jurisprudence, doctrine, legislative and judiciary cuts, and genealogy as explanation of those speeches in relation to the historical practices inside which they occur; genealogy together with archeology, should establish the novelty, the simultaneously historical and political event (relationships involving power, knowledge and oneslf) represented by these same practices.