The present study used a plant mediated green synthesis of iron oxide nanoparticles (Fe3O4NPs) through the chemical reduction of 10 ml of 0.005M FeCl3.6H2O solution and 1ml of 8 g palm seed extract as reducing as well as coating (capping) agent. The move towards extracellular synthesis of iron oxide (Fe3O4) nanoparticles using palm seed appears to be cost effective, eco friendly to that of conventional methods of iron oxide (Fe3O4) nanoparticles synthesis. It was observed that the use of palm seed extract which makes a fast and convenient method for the synthesis of iron oxide (Fe3O4) nanoparticles within a short period of reaction time. Aqueous extract of palm seed was produced and subjected to phytochemical investigations for determination of phenol, flavonoids, alkaloids, glycosides, Tannins, and saponin. Sunlight induced green synthesis of iron oxide (Fe3O4) nanoparticles was performed by treating the aqueous extract with ferric chloride hexahydrated (FeCl3.6H2O) in different ratios. The formation of iron oxide ((Fe3 O4) nanoparticles was visually confirmed by the colour change of the mixture and further characterized by using UV– Vis absorption spectroscopy method. It exhibited a distinctive absorption peak in the UV/Vis spectrum between 200 and 300 nm. The UV-Visible spectrum of the colloidal solutions has absorbance peaks observed at 261 nm. XRD is used to assess the crystallite of synthesized nanoparticles since have high intensity or peak appear at 2θ = 22°. The average particle size of magnetite nanoparticles, as determined by the X-ray diffraction method, was found to be 5.8 nm which showed a cubic spinel structure of IONPS .FTIR data reveal to identify the potential bio-molecules in the seed extract responsible for the reduction and also the capping reagent responsible for the stability of the bio-reduced iron oxide nanoparticles. The antibacterial activities of IONPS were evaluated against Escherichia coli (gram -ve) bacterial strain and Staphylococcus pyogens (gram +ve) bacterial strain test organisms.