Viscoelastic and dielectric properties of composites with polyvinyl chloride as major matrix constituent, ethylene vinyl acetate (EVA) as polymeric plasticizer, and wood flour (WF) and fly ash (FA) as filler have been studied. The effect of variation of WF, FA, and EVA on storage modulus E', loss modulus E '', and glass transition temperature, T-g, has been evaluated using dynamic mechanical analysis (DMA). Effect on permittivity and conductivity is evaluated using dielectric analysis. The results show considerable influence of constituents of the composite on the properties evaluated. DMA shows that WF contributes to an increase in T-g, E', and E '' and a decrease in loss tangent, tan delta. The FA content has insignificant effect on these properties. Increasing WF content increases epsilon'. POLYM. ENG. SCI., 50:1253-1260, 2010. (C) 2010 Society of Plastics Engineers