The paper is devoted to methodological approaches towards financial diagnostics of public companies in emerging financial markets. The research purpose was to systematize relevant methodological approaches in the context of investment monitoring with an emphasis on the level of financial development. The methodology was based on the results of theoretical analysis, which allowed to formulate the principles and concept of systematization. It was revealed that the specificity of financial diagnostics in the research area is associated with its theoretical, methodological and information maintenance. Within the framework of investment monitoring, the theory and methodology of financial diagnostics combines the subject areas of bankruptcy forecasting, investment valuation and macrofinancial analysis. The main diagnostics tools are represented by financial models of bankruptcy prediction. In particular, it is possible to apply structural models based on market indicators, but the feasibility of their use should be tested taking into account information limitations. In general, financial diagnostics of public companies in emerging financial markets requires a comprehensive approach that appeals to market and specific factors of financial health of issuers, adjusted for the level of financial development.