The article deals with the analysis of legal acts regulating the reform of organizations with irregular Cossack troops on regularly during Hetman I. Mazepa and C. Razumovsky. The main objective of these reforms was to improve the fighting capacity of the Ukrainian army, by creating wage, convivial and regiments, as well as the adoption of regulations governing the procedure for execution of reports, orders, military parades, military service, paid, providing a form of food and fodder.