The synthesis and characterization of polyaniline (PANI)/poly vinyl formal (PVF) blend films were carried Out in this work. Polyaniline base was doped using dodecylbenzene sulfonic acid (DBSA). These blend films were characterized by UV-Visible, FTIR spectra and scanning electron microscopy (SEM) to investigate their optical, structural and morphological properties. It was found that the percolation threshold of these blends is 4.4 wt% of PANI. The dc and ac conductivities of these blend films have been measured at a temperature range from 300 to 100 K in the frequency range of 10 kHz to 1 MHz. The electrical conductivity of the blend films enhanced with the increase of polyaniline amount up to a value of 2.5 x 10(-4) S cm(-1) at 65 wt%(, of polyaniline. The dc conductivity of the PANI/PVF blend films follows the three-dimension variable range hopping. Temperature variation of frequency exponents in this blend suggests that ac conduction is attributed to be correlated barrier hopping. (C) 2008 Elsevier B.V. All rights reserved.