The article analyzes the main characteristic features of the philosophy of religion of the founder of the Marburg school of neo-Kantianism Hermann Cohen. Special attention is paid to Cohen's criticism and reinterpretation of Kant's “practical philosophy” from the point of view of the philosophy of religion: Cohen supplements and expands Kant's provisions on moral law and moral duty, interpreting them as divine commandments. The authors emphasize the fundamental importance for Cohen of the “internal similarity” between Kant's ethical teaching and the main provisions of Judaism. The sources of Kant's own ideas about the Jewish tradition are shown, which include the work of Moses Mendelssohn “Jerusalem” and the “Theological-political treatise” by Baruch Spinoza. Cohen's criticism of these works is analyzed an much attention is paid to the consideration of Cohen's attitude to Spinoza's philosophical legacy in general. The interpretation of the postulates of Judaism by Cohen (and their “inner kinship” with Kant's moral philosophy) in ethical, logical, and political contexts is presented. Cohen's understanding of such religious-philosophical and doctrinal phenomena as law, grace, Revelation, teaching, the Torah, messianism, freedom, the Old Testament and the New Testament, etc. is provided and analyzed. The main points of Cohen's religious teaching as “ethical monotheism” are considered; in particular, the authors analyze his understanding of the idea of God as “the only one”, which is highlighted in the works of Paul Natorp. It is concluded that Cohen's philosophy of religion, which is based on the postulates of Judaism as well as Kant's “practical philosophy”, could be characterized by the terms “ethical monotheism”, “universalism” and “humanism”. © 2021 Saint Petersburg State University. All rights reserved.