The article considers the Agile methodology, its conceptual principless and studies the main accounting aspects of its implementation in realizing the projects of software development. In order to meet the modern requirements of the economic environment, the IT companies are turning to Agile-methodologies with accent on iterative and incremental software development. The software development on the basis of a flexible approach has numerous advantages, in particular centering on clients' needs, reducing risks and costs, providing a transparent process. However, using Agile-methodology can make accounting a complicated task. The existing accounting principles involve software development in a long-term perspective and in more discrete phases. The article analyzes the popularity of practical use of Agile approach and determines the advantages from its use as well as defines the accounting related problems. The ways of eliminating the complications of using the flexible approach in project management in financial accounting are defined. The main ideological aspects of Agile Manifesto are considered. In modern conditions, almost all businesses are in a state of constant change. There are purposeful transformations of both their individual elements and the management system in general, which requires manageability of change, which is difficult to achieve even within individual projects, often unique and innovative. In addition, the world economy has undergone significant changes in the economic environment, due to the globalization of business, informatization of society and the transition to a new model of economic growth. It is investigated that with modern optimization of financial processes Agile-technologies are built in such a way that changes are welcomed and uncertainty is recognized. And this did not bypass the internal audit. The growing needs of customers, the need to change process technologies, the introduction of new methodologies in the activities of departments adjust the internal audit to change approaches to testing and analysis of materials, as well as active participation in new projects.