This work presents the influence of the weight fraction of multi-walled carbon nanotubes (MWCNTs) in the poly(dimethylsiloxane) matrix on electrical insulating and morphological properties of the composite films. Atomic force microscopy surface topography maps showed good dispersion of MWCNTs within the polymer matrix without aggregates on the surface. Using of broadband dielectric spectroscopy measurements, it was found out that the percolation threshold of composite films lies in the MWCNTs concentration range of 0.5 -1.5 wt. % in polymer matrix. For nanocomposites above to the percolation threshold, the impedance response showed a shift from conductive to dielectric-like behavior as frequency is increased. This global impedance response is attributed to the presence of conductive particles distributed in an insulating polymer matrix acting as a complex network of local resistors and capacitors.