The article is devoted to the study of one of the most relevant and widely used tools of the modern decision-making process at the national and international levels – cost-benefit analysis (CBA). The article defines the purpose of the cost-benefit analysis. Three approaches to the selection of CBA stages are analyzed, among which there are three, from five to seven and ten stages. Their advantages and disadvantages are highlighted. The modern stages of the analysis of benefits and costs are systematized, namely: determining the level of analysis and its purpose; identification of alternatives to the public project; identification of the list of benefits and costs of the project; valuation in monetary terms of certain benefits and costs; establishing project evaluation criteria; discounting benefits and costs to obtain the present value of the project; determination of the net present value of social project options; analysis of the sensitivity of the social project; analysis of the distribution of existing benefits from the public project and selection one project among several alternative ones for implementation. The figures of the choice of existing alternatives of the public project are analyzed. Existing types of project costs are identified, including direct, indirect, tangible, intangible, opportunity and real costs. The list of benefits investigated by the analysis is determined, which include: monetary, non-monetary and intangible benefits. The difference between monetary valuation of project benefits and costs at shadow and market prices is investigated. The most common selection criteria in the modern project decision-making process are analyzed. The peculiarities of the formation of the social discount rate are highlighted. The features of sensitivity analysis and the purpose for its implementation are determined. Existing types of uncertainty and ways to overcome them are summarized, namely knowledge uncertainty, policy uncertainty and future uncertainty. The specifics of decision making in the cost-benefit analysis are studied. Further directions of research of problematic questions of the cost-benefit analysis in modern economy are identified.