The article discusses the influence of geopolitical competition on the position of military-service corporations of South-West Russia. Based on the analysis of the mobilization capabilities of military-service corporations, the authors come to the conclusion that they are relatively effective exclusively in the geopolitical situation of defense, and not offensive. Hetman's Ukraine turned out to be the least effective in terms of military and civil mobilization, despite the concessions and indulgence of the Russian government. It was especially in contrast with the high level of combat readiness of the Cossacks of the Don Army. The lack of motivation to reform the military-service corporations until the mid-1760s is explained by the fact that the government has serious alarmist sentiments in front of the threat from the South (Crimea, Turkey), despite the peace there preserved. For this reason, the defense system retained its relevance, relying on the resources and structures of military service corporations of the South-West. This also contributed to the intensification of Russian foreign policy in Central Europe. After the completion of the Seven Years War for Russia, the coming to power of Catherine II and the establishment of the Northern System foreign policy of N. I. Panin, favorable conditions arose for the transition to an offensive in the south. In turn, this put on the agenda for the Russian government both the question of preserving the military-service corporations, which showed their military effectiveness, and the question of eliminating those who did not use it, using the saved resources to strengthen the regular imperial army.