The freedom issue has not been systematically considered by Ockham; that is why the author approaches it from the point of view of the methodological principles examined by the Venerabilis Inceptor in order to reach its development. First, the basis for the new gnoseo-ontological justification of the reality proposed by the Ockham's followers is established. That makes it possible to set the limits in which the issue is framed according to a model strongly inspired in the principle of divine omnipotence. Ockham's approach uses the Aristotelian language and doctrine of free will, but from a completely different point of view; since the Aristotelian free will results from a first recognition of a number of possibilities from which the agent opt; then freedom is an intellectual capability. Ockham sets aside this key element of Aristotelianism by changing the approach of study; he supports that will is an active power and its key option -acting or not acting- does not depend on the human intellect but on itself as a causa sui. Metaphysic and Anthropology, which support this belief, have been materially changed as compared to the main trends of the XIII Century: nature lacks a specific direction; it is not determined by truth and good. Only the free and conscious agent acts towards and end established by himself while the physical universe is predictable and perfectly determined. Freedom is shown as a new reality against natural determination, thus shaping the first medieval version for the modern dilemma of freedom versus determinism.