The present study deals with the immobilization of ZnO nanoparticles (NPs) as nanofiller inside poly(vinyl alcohol) (PVA) by solution casting method which is a lowcost, environmental-friendly, and rapid method of sonochemistry. Firstly, the surface of ZnO NPs was treated by bovine serum albumin (BSA) in the phosphate-buffered solution under ultrasonic cavitation. Three diverse polymeric nanocomposites (NCs) are formed by changing the percentage of ZnO@BSA NPs (3, 6, and 9 wt%) with same amount of PVA. The structure properties, morphology, and thermal stability of prepared NCs were determined through Fourier transform-infrared spectroscopy, X-ray diffraction, energy-dispersive X-ray spectroscopy (EDX) and optical UV-Visible spectrum, transmission electron microscopy (TEM), and field emission scanning electron microscopy. The presence and the dispersal of the ZnO@BSA NPs in the PVA matrix were recognized by TEM. In the X-ray diffraction analysis, the values of mean particle size using Debye-Scherrer equation were estimated in the range 4 to 6 nm that is almost in agreement with TEM analysis. Increase of 14% in thermal stability and also increase of more than 2-fold of the tensile strength of PVA/ZnO@BSA NC 9 wt% in respect to the pure PVA showed that the modified NPs well dispersed within PVA and attached to it. KEYWORDS bovine serum albumin, nanocomposite, poly(vinyl alcohol), ultrasound irradiation, ZnO nanoparticle