The aim of this paper is to recover Kaldor´s propositions to shed some light on the recent debate about industrial productivity in Brazil. Nowadays, it is a well-disseminated idea that the opening of the economy has contributed to the increased industrial productivity in the nineties. However, theoretical arguments have emphasized supply sources as the main cause of such an increased productivity. Following the Keynesian tradition, Kaldor emphasizes the importance of the aggregate demand components to explain productivity growth. In conclusion, we call attention to the fact that sustainability of productivity growth depends basically on the factors working on the aggregate demand side.