Is the creation of the New Development Bank (NDB) and the Asian Infrastructure Investment Bank (AIIB) a challenge for the World Bank and other traditional multilateral development banks (MDBs)? This paper provides an initial assessment of the potential benefits and risks of NDB and AIIB by examining their motivations, scale, structures, rules and first projects. It identifies areas in which the new MDBs can complement the World Bank and other traditional MDBs and discusses ways in which they can undermine the latter. It suggests ways in which the two types of MDBs can further their cooperation in development financing.