The article examines the provisions of the catechisms of the Ukrainian Greek Catholic Church regarding the war and its challenges, as well as the defense of the Motherland. A comparative analysis of relevant thematic instructions in the Catechism “Christ is our Easter” (published in 2011), the Catechism for youth “We walk with Christ” (published in 2021) and the “Catechism of the Christian Warrior” (published in 2022) was carried out. It was determined that the provisions of the UGCC's own fundamental doctrinal documents, its Catechisms, regarding the problems of war and defense of the Motherland, were formed, clarified and supplemented according to the circumstances and needs of the time. The catechism of the UGCC “Christ is our Easter” contains general Christian considerations on the subject under consideration, which are principled, establishing, and refer to how civilized peoples should conduct themselves. The catechism for youth, created in the previous years of the undeclared Russian Federation's “hybrid” war against Ukraine, covers the issues related to the war and the defense of the Motherland in a substantive way and closer to current Ukrainian realities, although it still has some idealistic approach. The Catechism of the Christian Warrior, the preparation of which was completed and the publication was carried out during the full-scale military offensive of the aggressor, is a set of thorough and competent advises for Ukrainian soldiers, where things are called by their names, and there are no provisions that can cause doubts due to experience and be problematically achievable for implementation. Therefore, it is concluded that especially this Catechism, together with and in addition to the two previous ones, is a useful and timely contribution of the UGCC to the instruction of Ukrainians during the war, and therefore to Ukraine's victory over the enemy.