The use of beryllium as a neutron multiplier for fusion reactor blankets has been analyzed. The analysis has been performed based on designs for a helium-cooled ceramic breeder and a self-cooled liquid-metal blanket, which have both been suggested for the Next European Torus reactor. It is shown that the use of beryllium in a ceramic breeder blanket is best in a “sandwich-type” arrangement, where a beryllium block is embedded between a thin ceramic layer and the thick main breeding zone, or in a homogeneous mixture of beryllium and breeding ceramics. The sandwich-type solution needs only a minimum of beryllium inventory. Monte Carlo calculations show that heterogeneity effects in such a blanket are negligible. Therefore, the “homogeneous” solution can be achieved in a more heterogeneous arrangement like slabs of beryllium with the breeding ceramics in between. The use of beryllium also provides a benefit for liquid-metal blankets, using either LiPb or lithium metal as breeding material, since neutron multiplication and the tritium breeding ratio are enhanced in such a way that it is possible to reduce the blanket thickness considerably or to replace the inboard breeding blanket by a simple neutron reflector. It turns out that in such a blanket the use of lithium metal as breeding material is superior to that of LiPb.