Lanthanum-doped bismuth titanate (Bi 3.25La 0.75Ti 3O 12 or BLT) is important ferroelectric materials for FeRAMS, which need further improved by substituting isovalent cations to assist the elimination of defects such as oxygen vacancy. In this work, fabrication and investigation of substituting Mn 4+ for Ti 4+ ion on B-site of Bi 3.25La 0.75Ti 3O 12 ceramics were carried out. X-ray diffraction patterns of BLTMn ceramics indicated orthorhombic structure with lattice distortion, especially for samples with higher concentration of MnO 2 dopant. Microstructural investigation showed that all ceramics composed mainly of plate-like grains. An increase in MnO 2 doping content increased diameter and thickness of grains but reduced density of the ceramics. Electrical conductivity was found to decrease while dielectric constant increased with Mn 4+ doping concentration. © 2012 Elsevier Ltd and Techna Group S.r.l.