Single phase orthorhombic tungsten-bronze (OTB)ceramics of Pb2Bi3NdTi5O18 (PBNT) were prepared by a high temperature solid-state reaction method. Electrical impedance, phase angle, dielectric constant and dielectric loss have been measured in the frequency range 0.1 kHz-3 MHz in the temperature region 16-250 degreesC. Dielectric studies show relaxor behaviour with a diffuse phase transition having diffusivity parameter value 1.85. AC impedance analyses suggested the phase element to be capacitive. The Cole-Cole plot indicated high resistance of the sample at room temperature. The activation energy (E-a = 0.63 eV) has been estimated from the temperature variation of DC resistivity. (C) 2003 Elsevier B.V. All rights reserved.