The methodological and practical recommendations for the use of a process model for forming the optimal structure of financing sources at business enterprises under conditions of Ukraine's economic revival are substantiated. Despite the existence of some proposals regarding the mechanisms for forming the optimal structure of sources of financial resources at the level of business structures, the practice of implementing their various components by stages of the project cycle is of great interest. The etymological content of the scientific category “financial resources of the enterprise” is generalized and the composition of own, attracted and borrowed financing sources is specified. At the conceptual level, the algorithm for the optimal ratio of equity and borrowed capital at business enterprises is recommended, which allows determining the directions of attracting individual sources of financial resources. Within the framework of the process approach, the author's version of the process model of forming the optimal structure of financial sources at business enterprises is proposed, with the following five stages: selecting the optimization criteria and determining the target structure of financing sources; comparison of the achieved structure of sources of financial resources with their target structure; identifying limitations; selection of alternatives for forming sources of financial resources; provision of feedback and transition to the stage of researching the target capital structure. When forming the optimal structure of financing sources at business enterprises, depending on the classification features, the author identifies the limitations that affecting the structure of financial resources, namely: legislative limitations (related to the timing of attracting and using various types of financial resources and to the peculiarities of the taxation system); industry limitations (taking into account the period of raising funds, the size of the enterprise's value added and the degree of intra-industry cooperation); market limitations or limitations imposed by capital market participants (credit limitations, financial or stock limitations, limitations related to the lack of credit history of the borrowing enterprise). The expediency of dividing the established limitations into general and partial ones is substantiated.