Robert Kane developed naturalized version of Libertarianism in his The Significance of Free Will. In this paper, his free will theory is critically examined. My criticism consists of two parts. In the first part, I argue that Kane’s theory is troubled by the problem of choice’s being matters of chance, and his account of ultimate control does not provide any solutions. It is also pointed out that though his position satisfies UR (the condition of Ultimate Responsibility), since it is only vacuously satisfied, the source of an agent’s purposes cannot be said to lie in the agent. In the second part, I compare Kane’s theory with a compatibilist theory, showing that his position gives no more freedom-elevating features than compatibilism. Thus it is concluded that Kane’s attempt fails as a libertarian theory.