This study demonstrates the efficacy of Aspergillus niger (A. niger) in the green synthesis of iron oxide nanoparticles (IONPs). A. niger filtrate was employed as a biogenic source for IONP production. Characterization of the synthesized IONPs using UV-Vis spectroscopy revealed a characteristic absorption peak around 320 nm, confirming nanoparticle formation. FTIR analysis identified the presence of fungal biomolecules, such as proteins and carbohydrates, on the nanoparticle surface, suggesting their role in capping and stabilization. XRD analysis confirmed the crystalline nature of the IONPs and indicated the predominant presence of the hematite  phase. Microscopic examination using SEM revealed a uniform, quasi-spherical morphology with particle sizes ranging from 36 to 44 nm. These findings highlight the potential of A. niger as a sustainable source to produce stable and biocompatible IONPs, suitable for diverse biotechnological and biomedical applications.