Subject. The process of documentation permeates all stages of testing and allows you to collect the required number of auditing evidence of adequate quality to express a reasoned opinion on the outcome of the auditing. Purpose. This issue was thoroughly examined from the theoretical and practical positions of Russian and foreign authors, but basing on the analysis of international standards on auditing (ISA), the clarified definition of working documentation of the auditor is presented in the article, as well as the requirements for its structure, order, registration, grouping, and storing were systematized, for the purposes of internal and external quality control. Methodology. In accordance with ISA the key information was identified that must be contained in the auditing file at the pre-contractual stage, the stage of planning, gathering auditing evidence and forming conclusions on the results of the inspection, the necessity to group the current and permanent auditing files was justified. Results. The authors of this article analyzed the significant issues of the auditing and their reflection in the auditing documentation. The features of the formation of the auditing documentation in the validation of small farms were revealed. Conclusions. Methodological support of self-regulatory associations of auditors is required in the development of a unified approach to the formation of the working documentation that will assist in the improving of the quality of professional services; as well as streamlining the interaction of different auditing organizations in conducting joint projects, particularly in subcontracting; and it will also result in the reduction of claims from the external quality control for formal characteristics of the documentation.