The article is aimed at determining the level of maturity of the business process management system of an agro-industrial enterprise. The existing common approaches to assessing the maturity of the business process management system are identified, their defining features are determined. A definition of maturity of the business process management system of the enterprise is made. The features of the process and enterprise maturity model (PEMM) developed by M. Hammer are described in detail. Four levels of business processes that form the system according to the Hammer model are characterized. The aspects and directions of research of maturity of the business process management system of enterprise according to the PEMM model by M. Hammer are specified. The scale of assessment of the level of maturity of the business process management system of enterprise according to certain criteria is provided. The procedure for assessing the maturity level of the business process management system of the enterprise under research is described and a scale is provided that helps to determine the current level of maturity of the system from the very low to the very high (five such levels are defined in general). Descriptions of the levels of business processes according to the PEMM model are specified in terms of the aspects of Projecting, Contractors, Process Owner, Infrastructure and Indicators. For each aspect, an assessment of the business process management system of the enterprise under research was carried out. The results are presented both by a separate direction and by each aspect of the assessment of the maturity of the business process management system of enterprise. For each aspect of the assessment of the system maturity, the characteristic features are determined, the main disadvantages and achievements are indicated. On the basis of the determined estimates of the business process management system of the enterprise under research, an assessment of the maturity of the business process management system of this enterprise in view of certain aspects is computed, as well as its current level is defined. To identify the most problematic areas in the business process management system, the existing level of maturity of the system is depicted using a petal chart. The main directions of further improvement of the existing system are defined.