Objective:

Systematize the theoretical foundations on the necessary interrelation of investment and financing decisions for the evaluation of the investment process through the criterion of the weighted average cost of capital.

Materials and methods:

The methodology of systematic descriptive review and narrative review was used in an integrated manner, with the bibliometric analysis technique, which allowed the identification, selection, evaluation of the source and analysis of the data, abstractions, decomposition and generalities of the topic objectively, according to the criteria of the authors of the sources and of this article.

Results:

It was demonstrated that the interrelation of investment and financing decisions, as part of the company's strategic decisions, allows obtaining a budget that constitutes the financing necessary for the execution of the best investments with the minimum cost of the operations financing sources used.

Conclusions:

The international theoretical premises regarding the weighted average cost of capital were based on the need to interrelate investment and financing opportunities, since it allows the decision to be made to accept the most profitable project for the company, those whose internal rate of return is greater than the weighted average cost of capital.