Physicochemical characterization of CeO2NPs using UV–vis, FTIR and XRD have confirmed the characteristic identity and fluorite phase of their crystalline nature. The interaction studies between cerium oxide nanoparticles (CeO2NPs) and HSA were investigated using fluorescence emission and synchronous spectra, UV–vis absorbance, FTIR, FT-Raman and Circular Dichroism spectroscopy. Thermodynamic parameters and Stern-Volmer plot has conveyed the existence of the ground state complex raised due to static quenching. Synchronous and Three-Dimensional fluorescence spectra have conveyed the affinity of CeO2NPs towards Trp and Tyr residues. Results obtained from the FTIR and FT-Raman studies have evidenced minor changes in the amide and amino acid residues band position. Circular Dichroism studies have quantified the conformational changes due to the loss in their alpha helical contents of the secondary structures. Fibrillation studies using Congo red (CR), Thioflavin T (ThT) and Tryptophan emission (Trp) assay have suggested the promoting role of CeO2NPs against HSA fibrillation. CD studies have shown the enhanced percentage of beta sheet structures in the fibrillar samples that reconfirm the increased effect of CeO2NPs during the fibrillation process. © 2017 Elsevier B.V.