[en] In this study, polyhydroxyamide (PHA) hybrid nanocomposite films containing multi-walled carbon nanotubes (MWCNTs) and clay as reinforcing materials were fabricated, and the effects of the simultaneous use of nanoparticles on the mechanical, thermal, and electrical properties of the hybrid nanocomposite films were analyzed. Interestingly, it was found that the MWCNTs and clay form a three-dimensional (3D) network structure inside the PHA matrix, and that this unique structural characteristic has a significant influence on the improvement in the mechanical properties of the hybrid nanocomposite films. For instance, the tensile strength and initial modulus of a PHA hybrid nanocomposite film containing 1.0 wt% MWCNTs and 3.0 wt% clay were 102.5 MPa and 1.63 GPa, respectively, which are increases of 28.6% and 30.4% when compared with a neat PHA film. However, despite the excellent reinforcing effect, an interesting phenomenon was also identified in that the network structure formed by clay interferes with the electrical conduction network of the MWCNTs and hinders the thermal cyclization behavior of the PHA hybrid nanocomposite films.