One of the most important contributions of Sraffian economists to economic theory consists in the argument that both the aggregate and the general equilibrium versions of the neoclassical theory of value suffer from a logical inconsistence that prevents them from identifying a long-period position. The aim of this paper is to show that also Sraffa’s own approach, based on the assumption of given sectoral outputs, brings about an inconsistence between his theory and the long-period method. The main upshot of our argument is that sectoral outputs can legitimately be left to a separate stage of the theory only insofar as the long-period method is dropped and the classical-type theory is reshaped and casted within the temporary equilibrium method.