Particle accelerators are replacing reactors as neutron production sources with the aim of starting the era of hospital-based BNCT. In this chapter we review the two basic technologies used for these accelerators, namely, electrostatic (ES) and radiofrequency (RF). We shall restrict ourselves to relatively low-energy accelerators, i.e., accelerators producing proton or deuteron beams of energies less than 10 MeV and high intensity (tens of mA), in order to minimize the production of induced radioactivity which is an important limiting factor in a hospital environment. The general principles of these two types of accelerators will be reviewed, and the different present efforts to develop such facilities worldwide will be described.