BaCu(B 2 O 5 ) (BCB) ceramic powder was used to decrease the sintering temperatures of BaSm 2 Ti 4 O 12 (BST) and BaNd 2 Ti 5 O 14 (BNT) ceramics. The sintering temperature of the BST and BNT ceramics was reduced from approximately 1350°C to 850°C by the addition of BCB. The bulk density of the specimens increased and reached the saturated value with increasing BCB content. The variation of the dielectric constant (ɛ r ) was similar to that of the bulk density and, thus, the relative density plays an important role in determining the ɛ r value of the specimens. The Q-value initially increased with the addition of BCB but decreased considerably when a large amount of BCB was added because of the presence of the liquid phase. Good microwave dielectric properties of Qxf=4500GHz, ɛ r =60 and τ f =−30ppm/°C were obtained for the 16.0mol% BCB-added BST ceramics sintered at 875°C for 2h.