In this doctoral thesis, titled The Problem of Abolishing Ethics in Zagreb Praxis School, the author analyzed the demand for the abolishment (Aufhebung) of ethics, elaborated in the Zagreb Praxis School. This demand was voiced by Milan Kangrga and supported by Gajo Petrović. In the first chapter, entitled Previous Clarifications, the author discussed the label Zagreb Praxis School, the concept of abolition (Aufhebung), and the difference between ethics and morality. As the demand for the abolition of ethics is elaborated in the tradition of Marxist philosophy, the second chapter outlined the discussion on the possibility of Marxist ethics. The third, most comprehensive chapter, consists of four parts. In the first part of the chapter, the author presented the basic concepts of Milan Kangrga's philosophy. Uncovering the foundations of Kangrga's philosophy proved necessary for understanding the author's critique of ethics and morality. In the second part of this chapter, Kangrga's and Petrović's critique of philosophy and science is discussed. In the third part of the chapter, aspects of the critique of ethics and morality are discussed, with special emphasis on approaches to the discrepancy between is (Sein) and ought (Sollen). In the fourth part of the chapter, the author analyzed Kangrga's theory of human nature. The author distinguishes between several understandings of morality in the Kangrga's and Petrović's writings: morality as an ideology, morality as conformism, morality as moralizing, and morality as indignation that is the impetus for action. The author also distinguishes between the critique of ethics as a science, the critique of ethics as a theory, the critique of ethics as a (separate) discipline, the critique of the necessary normativity of ethics, and the critique of ethics as compensation in the context of alienation.