The article is devoted to the substantiation of the necessary transformation of the approach to the budget efficiency assessment when dealing with the investing decision. The position of the authors is confirmed by the change of the conception of the federal investing policy for the period up to 2010 as well as by the refusal from the direct federal financial support of the profitable projects. The article proves the possibility to use duration in order to define necessary and sufficient terms of the budget efficiency assessment when dealing with the investing decision. The article describes the order of duration calculation when the budget efficiency of profitable projects is assessed.