Multi-functional polyester fabric with magnetic, antibacterial and sono-Fenton catalytic activities was prepared by in situ synthesis of magnetite and hematite nanoparticles using ferric chloride, ferrous sulfate and sodium hydroxide. The process was carried out at two different temperatures, 100 °C and 130 °C, resulting in Fe₃O₄ and α-Fe₂O₃ nanoparticles. The morphology, crystal phase, thermal stability, magnetization properties and chemical structure of the fabrics were characterized by scanning electron microscopy (SEM), X-ray diffraction (XRD), differential scanning calorimetry (DSC), vibrating sample magnetometry (VSM) and energy dispersive X-ray spectroscopy (EDX). The tensile properties and colorimetric values of the treated fabrics were also measured. It was found that Fe₃O₄ and α-Fe₂O₃ nanoparticles with average crystal sizes of about 11 nm and 17 nm were synthesized on the fabrics treated at boiling point and 130 °C, respectively. The uniform distribution of the iron oxide nanoparticles on the fiber surface was confirmed by SEM and EDX. Moreover, the iron oxide nanoparticles had different coloring effects on the treated fabrics confirmed by reflectance spectra. The magnetite and hematite treated samples showed reasonable saturation magnetization values of about 7.5 emu g⁻¹ and 0.1 emu g⁻¹, respectively. Interestingly, the tensile properties of the treated samples were enhanced compared with the untreated fabric. These findings suggest the potential of the proposed method in producing fabrics with durable magnetic properties that are suitable for various applications especially electromagnetic shielding, excellent antibacterial activity against Staphylococcus aureus and promising sono-Fenton catalytic ability for dye discoloration.