Sodium bismuth titanates Na 1/2 Bi 1/2 TiO 3 (NBT) doped with 0-3 wt% Er 2 O 3 were prepared by the conventional solid-state reaction method. The X-ray diffraction results revealed that the sintered Er-doped NBT ceramics exhibited a pure perovskite structure with Er 31 concentrations ranging from 0 to 1 wt%. At a low Er 2 O 3 concentration, the Er-doped NBT ceramics showed enhanced electrical properties with dielectric constant e 33 T / e 0 5 636, a low dielectric dissipation factor (tan d 5 3.3%), a low coercive field (E c 5 4.56 kV/mm), and a high piezoelectric constant (d 33 5 75 pC/N). The relationship between the composition and properties of Er-doped NBT ceramics has been discussed.