Justifying the decisions regarding the investment projects that are going to be implemented by companies is based on a series of efficiency criteria which reflect the most important aspects of the investment process tied to the obtained results in accordance with the expenses. Considering the opportunity cost of the invested capital and the time’s influence on value, making the investment decision is not an easy task. The paper presents aspects regarding two important criteria used in substantiating the economic efficiency of the capital investments: the net adjusted present value and the internal rate of return

economic efficiency, capital investments, net adjusted present value, the internal rate of return, substantiating decisions