The scientific article is devoted to the problems of legal regulation of the engagement by the State Audit Service of Ukraine of qualified specialists on a contractual basis for conducting state financial audit. The relevance of the topic is substantiated by the existing practice of the State Audit Service involving third parties in the implementation of state financial control measures. This practice stems from the absence of "in-house" qualified specialists within its staff, as well as identified cases of engaging individuals without concluding appropriate contracts and persons who, at the time of their participation in control measures, lacked proper evidence confirming their qualifications. It has been established that the right of the State Audit Service to engage qualified specialists on a contractual basis is regulated by a number of normative legal acts of sectoral legislation. Among them, one of the departmental acts was issued in the form of methodological recommendations, despite possessing the characteristics of a normative legal act. It is substantiated that the specific features of the legal regulation of the activity of the audited entity determine the criteria for recognizing engaged specialists as qualified, as well as the conditions, types, forms, and procedures for concluding contracts applied in the relevant field. It has been proven that the definition of the contract directly depends on its subject matter, which is in fact determined by the needs of the State Audit Service to obtain specialized knowledge during inspections in order to fulfill the tasks of state financial audit. By comparing judicial expertise with scientific and scientific-technical expertise, it has been established that they share a common feature: only recognized qualified specialists may directly perform them, that is, persons who have undergone the state accreditation procedure (experts conducting scientific and scientific-technical expertise) or attestation in a specific specialty (forensic experts) and have received the relevant certificates by which the state has confirmed their qualifications. It has been proven that, for the practical engagement of qualified specialists on a contractual basis to conduct state financial audit that requires special expert knowledge, the State Audit Service must: adopt a decision on conducting the relevant expert study, act as its customer, and, after selecting the organizer in accordance with the procedure established by the Law of Ukraine "On Public Procurement," conclude a paid contract with such organizer. The content of this contract must comply with the requirements of Article 22 of the Law of Ukraine "On Scientific and Scientific-Technical Expertise," or conclude a paid contract for conducting an expert study with a forensic expert in accordance with Articles 7-1 and 13 of the Law of Ukraine "On Forensic Expertise". It is summarized that conducting state scientific and scientific-technical expertise or an expert study by a forensic expert without concluding the relevant contract constitutes a direct violation of the current sectoral legislation.