This paper provides a critical assessment of macroprudential policies at the theoretical and practical levels focussing on the case of developing economies, including Africa, Asia and particularly Latin America and the Caribbean. It argues that macroprudential regulation remains an elusive concept and is of limited applicability. At the theoretical level, within mainstream economics, macroprudential regulation can only be rationalized by arguing that the growth and development of the financial sector creates market imperfections that lengthen the intermediation chain, weakening the link between savings and investment. Thus, from this perspective the purpose of macroprudential regulation is to ensure that savings flows into investment. At the practical level, survey evidence shows that there is no agreement on the meaning of financial stability and even less so of systemic risk. Also, macroprudential regulation is not identified as being a priority among financial regulators. Macroprudential regulation focusses for the most part on the financial sector ignoring the fact that other economic sectors such as the non-financial corporate sector is a growing source of financial fragility due to its increased financialization. At a more general level, macroprudential regulations address, only partially, the financial vulnerabilities of developing regions such as those of Africa, Asia and Latin America and the Caribbean created by increased external financial openness and greater price flexibility.