The objective of the work was to identify and characterize the agribusiness companies concerning the use of the theory of capital structure for its financial activity. The capital structure is one of great importance, involving both investments and financings (both the capital of external parties' and their own). Methodologically, the research was characterized as descriptive conclusive, through an intentional sample of 69 agribusiness companies in the south of Minas Gerais. The objective was to know the characteristics as to the constitution of their own capital and that of external parties, in function of its investments and financing operations. The results showed that, in general, the action of the capital structure in generating values for the company has not been applied. Its use by most of the companies is related to the change of the capital structure through the medium rate of return. Therefore, the companies will rather work with their own capital in relation to the external capital, because they consider that the cost of capital of the existing loan policies in the market is high. Thus, the financial decisions are more related to investment opportunities than to the optimum combination of their own capital or the external capital.