Europe is lagging behind other developed economies in the availability and use of very fast broadband services. The recently introduced Digital Agenda for Europe initiative sets forward ambitious targets for the development of super-fast broadband infrastructures in Europe to foster smart and sustainable growth. This paper presents estimates of the costs of meeting these targets through the deployment of next-generation networks. Furthermore, the magnitude of the financing gap is estimated and public support mechanisms are discussed to complement market investment in areas with low financial viability for the investment. The rationale of public sector support is discussed in light of the expected economic benefits of NGNs to consumers and businesses.