The article deals with the issue of effective implementation of internal financial control in the field of defense procurement. The functions and tasks of the State Audit Service of Ukraine in modern conditions are clarified, as well as the specifics of its functioning during the period of the legal regime of martial law when conducting state financial audits, inspection, verification and monitoring of purchases, etc. The activities of the State Audit Service of Ukraine during the last reporting year were analyzed and the position regarding the importance of implementing preventive measures aimed at preventing possible offenses without applying appropriate sanctions to customers was justified. It was determined that monitoring is one of the most effective tools for preventing violations, preventing financial abuse and corruption, and is also the only control tool that works preventively. The legal mechanism for defense procurement planning, the formation of the main indicators of the procurement of goods, works and services that have a defense purpose, the peculiarities of information disclosure, adjustments, the organization of control and reporting on the progress of bidding, as well as the publication of information on defense procurements, have been defined. The transformational changes in the organizational and legal foundations of state financial control in the field of defense procurement over recent times have been analyzed. Zones of special risk in the field of defense procurement in modern conditions are singled out, in particular, when inspections and audits are carried out, and the position is substantiated that the algorithm for the effectiveness of internal financial control should be based on the return of transparency to the field of defense procurement with the simultaneous adoption of effective measures aimed at preserving confidentiality critically important information necessary to ensure the security of the state. The need to achieve a balance of transparency of budget expenditures on the basis of public procurement with the provision of reliable measures to observe the strict secrecy of the functioning of the military-industrial complex and the defense industry as a whole has been determined.