Conducting polymer composites of polyvinylferrocene and polypyrrole (PVF/PPy) were synthesized chemically by the in situ polymerization of pyrrole in the presence of PVF using FeCl3 as oxidant. Acetic (CH3COOH) and boric (H3BO3) acids were used as the synthesis medium. Effects of the synthesis medium on the properties of the PVF/PPy composite were investigated. The PVF/PPy composites and homopolymers were characterized by fourier transform infrared spectroscopy (FTIR), thermogravimetric analysis (TGA), scanning electron microscopy (SEM), energy dispersive spectroscopy (EDS) and magnetic susceptibility techniques. Conductivity measurements were performed using the four-probe technique. We found that the conductivities of PVF/PPy-H3BO3 (1.19 S cm(-1)) and PVF/PPy-CH3COOH (4.510-1 S cm(-1)) increased relative to those of the homopolymers of PPy-H3BO3 (2.110-2 S cm(-1)) and PPy-CH3COOH (1.210-2 S cm(-1)) due to the interaction of PVF with the pyrrole moiety. The stability of all homopolymers and composites were investigated by thermogravimetric analysis and by conductivity measurements during heating-cooling cycles. There was a small drop in conductivity caused by the annealing of PVF/PPy composites at 70 degrees C. The conductivity of all samples increased with temperature and exhibited stable electrical behavior with increasing temperature. TGA analysis of samples showed that the composites were more stable than the homopolymers or PVF separately. The magnetic susceptibility values of samples were negative, except for PVF/PPy-H3BO3. Morphology changes of the composites investigated by scanning electron microscopy (SEM), attributed to synthesis conditions, have a significant effect on their conductivity.