The purpose of the article is to develop a methodology for diagnosing the effectiveness of making and implementing management decisions in entrepreneurial subjects.

Research methods. The methodological basis is general theoretical and specific methods of economic research, which allow solving problematic scientific problems. The research was based on the dialectical method of cognition of economic processes, scientific developments and publications of domestic and foreign scientists on the theory of decision. Theoretical generalizations and conclusions were made using the abstract and logical method (namely, scientific abstraction, analogy and comparison, induction and deduction, analysis and synthesis).

Research results. The results of the conducted research have showed that the effectiveness of any management decisions depends on the peculiarities of methodology of idea implementation in practice. Approaches to their substantive content regarding specific features of managerial decision-making should be identical to decision-making process. Establishing an effective decision-making mechanism depends on identifying conceptual elements of the decision-making process, which will further facilitate effective implementation and achievement of the set goals. In the research process, technique for diagnostics of the effectiveness of making and implementing managerial decisions in the entrepreneurial subjects was improved. Formula for calculation of diagnostics estimation of making efficiency process and implementation of management decisions at enterprises was presented.

Elements of scientific novelty. As an element of novelty, there were proposed an advanced diagnosing technique of the effectiveness making process and implementing management decisions at enterprises and an approach to its evaluation. A model for optimal combination of components of the efficiency diagnostics process of making and implementing management decisions was developed and substantiated. The main problematic elements of the managerial structure that would influence on the effectiveness of the making process and implementing management decisions were identified.

Practical significance. The research results can be used in order to improve the effectiveness of management decisions and to achieve the goals.