The aim of this study is to investigate the effect of PbS/CdS nanoparticles concentration on the mechanical properties of polyvinylidene fluoride (PVDF)-based composites. For this purpose, nanocomposite samples with PbS/CdS nanoparticles at 1%, 3% and 5% concentrations were prepared and their tensile strength, Young's modulus and elonga-tion at break were analyzed. The results show that at 1% nanoparticle concentration, the tensile strength increased by 12%, providing a significant improvement in mechani-cal properties. However, when the concentration increased to 3% and 5%, a decrease in mechanical performance of about 8% was observed due to agglomeration of nanoparti-cles and structural heterogeneity in the matrix. This study offers new perspectives for the optimization of PVDF-based nanocomposites and their effective use in industrial applications.