Polyurethane(PU) hybrid nanocomposite films containing graphite and multiwalled carbon nanotubes (MWNTs) were prepared by a solution-casting method, and their electrical properties and heating performance were investigated as a function of conducting hybrid filler content. The electrical resistivity of the PU/hybrid nanocomposite films decreased slightly from $2.40{ imes}10^2{Omega}cm$ to $2.79{ imes}10^1{Omega}cm$ with increasing the hybrid filler content (5.0~9.0 wt%). The current-voltage (I-V) characteristics of these nanocomposite films indicate a significant increase in current level with 9.0 wt% hybrid filler content, which reflects the fact that above the percolation threshold, the conduction mechanism in the nanocomposite films changes from tunneling conduction (nonlinear) to ohmic conduction due to the direct contact between the graphite and the MWNTs (linear). As a result, the PU/hybrid nanocomposite films containing 9.0 wt% hybrid filler with 4.5 wt% graphite and 4.5 wt% MWNTs can be quickly heated from room temperature to $48.8^{circ}C$ within 80 s by applying a DC voltage of 30 V, whereas the PU nanocomposite films containing 30.0 wt% graphite or 5.0 wt% MWNTs could only be heated to $39.2^{circ}C$ and $30.6^{circ}C$, respectively.