Abstract. This article examines the military-strategic importance of the Belarusian ally for Russia in connection with the events of the Special Military Operation in Ukraine. The author focuses on the fact that the concepts of combat and mobilization readiness of the armed forces are not identical to each other. Unlike the combat readiness, the mobilization readiness of the Belarusian army has traditionally remained low. Due to defense budget limitations, the ground forces had only skeleton personnel strength. The systematic preparations necessary to maintain the units in permanent readiness for deployment are neglected. Only a few Special Operations Forces are constantly on alert. Although the Belarusian military system was not initially focused on waging a major war, Belarus is strategically very important for Russia, primarily in the territorial geographical dimension.