The author in his master’s thesis examines the concept of criminal guilt and its need for regulating social relationships. In the beginning he briefly presents the theory of guilt in criminal law system, both from material and procedural perspective. The presumption of the concept of guilt is the existence of free will, which justifies the guilt and as a consequence legitimises punishment. The existence of free will has always been subject to philosophical debates, which are represented by the author through the arguments of determinists, libertarians and compatibilists. Despite different philosophical views that questioned the existence of free will and highly relativized this concept, the author is not satisfied with these conclusions and is searching for the explanations in the field of natural science as well. The latter are operating in accordance with the scientific method, which through constant doubt, questioning and testing of the proposed hypothesis, reveals the true nature of the world around us and within us. Mainly neuroscience and its findings have long been destroying our intuitive belief in the existence of free will and the concept of guilt. The author presents some of the most important research of the free will, which quite conclusively demonstrates that our brains operate in accordance with the deterministic laws of nature. In addition, human decisions and actions could be more and more precisely explained by mechanistic processes taking place in neural brain structures. Despite some opposing arguments of the critics, these findings suggest that the feeling of free will is merely an illusion and (criminal) guilt is in consequence only a fiction. Further on, the author gives attention to the arguments that argue the need for the concept of guilt in our legal system and for the regulation of interpersonal relationships. Among them, in particular the fact that the concept of guilt is consistent with our intuitions about human nature, and therefore the legal system cannot give up on the concept if it wants to be legitimate and effective, at least not until the general belief in public changes in this respect. The author also deals with the argument of incompatibility between scientific knowledge and normative regulation, since the phenomena these fields are studying and regulating are mutually incompatible. The last argument presented by the author is the need to punish as an inseparable part of human nature. Guilt as the presumption of punishment will endure, since punishment is an evolutionary programmed humans’ trait, intended to preserve the undisturbed functioning of human society, while at the same time also to satisfy our primitive motives to punish. In the end the author presents some solutions for the practice of punishment, uncovered by the discoveries regarding human nature and non-existence of free will (guilt), in particular the direction to utilitarian goals and alternative means in implementation of punishment and the omission of retribution. The author concludes that criminal guilt is still necessary for the society – for the functioning of its legal system and regulation of social relations – but could eventually, upon the change in people’s views on the concept of guilt (and the adoption of scientific arguments of determinism), become a redundant element of legal systems.