The effect of B2O3 addition on the sintering, microstructure and the microwave dielectric properties of the 5Li(2)O-0.58Nb(2)O(5)-3.23TiO(2) (LNT) ceramics have been investigated. It is found that the LNT ceramics could be sintered well at similar to 880 degrees C with low-level doping of B2O3 (<= 2 wt.%). Only Li2TiO3 solid solution (Li(2)TiO(3)ss) crystal structure could be detected for all the ceramics with various amounts of B2O3 addition from the X-ray diffraction (XRD) results. And interestingly, two phases with different color in SEM images are observed in B2O3-doped LNT ceramics. EDS results suggest that the two different phases are two Li(2)TiO(3)ss phases with different amount of Nb. In addition, there is no much degradation in the microwave dielectric properties with the B2O3 adding. In the case of 0.5 wt.% B2O3-doped samples sintered at 880 degrees C, good microwave dielectric properties of epsilon(r) = 22, Q xf = 32,000 GHz, tau(f) = 9.5 ppm degrees C-1 are obtained. (C) 2011 Elsevier B.V. All rights reserved.