0.5Pb(Zr 0.575 Ti 0.425 )O 3 –0.5Pb(Fe 2/3 W 1/3 )O 3 (0.5PZT–0.5PFW) belongs to the solid solutions which exhibits some bi-relaxor properties, with both ferroelectric and magnetic relaxor properties. Recently it was reported that the thin film of 0.8Pb(Zr 0.53 Ti 0.47 )O 3 –0.2Pb(Fe 2/3 W 1/3 )O 3 (0.8PZT–0.2PFW) has a new and very large magnetoelectric effect—switching from P r to zero with applied magnetic field of less than a Tesla. We report dielectric and ac electric conductivity investigations of the 0.5PZT–0.5PFW bulk ceramics. A detailed analysis of the temperature dependence of the universal dielectric response parameter s in terms of the theoretical model for tunneling of small polarons revealed that below 450K this mechanism governs the charge transport in the system. This provides a new understanding of the magnetoelectric effect in 0.5PZT–0.5PFW.