The relevance of the study is caused by the complexity of calculations when determining the cost for construction of agricultural facilities due to the multi-parameter system, which includes volume, structure, areas and objects of investment. Ensuring the effectiveness of capital investments through the use and implementation of advanced and latest solutions, technologies and other conditions of the investor in relation to the level of technical equipment and quality of the facility will allow obtaining a competitive facility and a profitable result. As a result of the study, the theoretical foundations of managing the cost of an investment and construction project were studied, an analysis of management methods and practical recommendations for justifying the cost of an investment and construction project were carried out in order to develop recommendations for cost reduction. The methodological basis of the study is: system analysis, methods of expert assessment, comparisons, analogies, analysis of absolute and relative indicators and others. To solve the problems, a combination of general scientific methods such as scientific observation, comparison, measurement, abstraction, modeling, induction and deduction, historical method, abstractions and concretizations, alongside specific methods including economic-statistical, analytical-calculation, functional-cost, and expert approaches were used. The practical significance of the work carried out is the development of a method for assessing cost management of an investment and construction project. The developed method has all the prerequisites for successful application in the real activities of the organization under study.