Moral luck is an important issue in meta- ethics. Its conflict to principle of control make challenges to moral moral assessment, moral judgment and moral responsibility. Bernard Williams is the first philosopher who uses the expression "moral luck" and tries to show that the contradiction between “moral” and “luck” is not so serious. Against Kantian’s idea and also our intuitions Williams doesn’t believe that morality is immune of luck and that unlike other values, is accessible to all people. If moral (...) value is accessible to all, according to his idea, it should be not only immune of luck but also supreme. Giving some examples, Williams by concepts like justification, regret and retrospective, shows that morality hasn’t these characteristics. Dividing moral luck into four types: resultant, circumstantial, constitutive and causal, Thomas Nagel puts Williams' moral luck under the first type and criticizes it. This study seeks to explain Bernard Williams’ viewpoint on moral luck. At first it clears types of moral luck, principle of control and its contradiction with moral luck, then after explaining Williams’ account of moral luck criticizes it. Nagel’s criticisms and others show that although they accept the existence of moral luck and also their account is compatible to williams’ but they deny williams’ success in defending of this phenomenon. Finally, despite of all critiques, it seems that Williams’ failure in defense of moral luck didn’t decrease the importance of this matter, but made some stronger ideas were appeared by Thomas Nagel in this regard. (shrink)