Nanoparticle embedded polysulfone ultrafiltration (UF) membranes were prepared by using the in situ embedment method, and the anti-biofouling properties of the prepared membranes were evaluated by conducting bacteria adhesion test, bacterium inactivation test and biofilm formation test separately. Among the several aluminum and/or silicon oxide nanoparticles tested, alumina (Al2O3) and Linda type L (LTL) zeolite nanoparticles were successfully embedded which could be evenly dispersed on membrane surface with high coverage ratio (38% and 49%, respectively) and were resistant to hydraulic shear detachment. The water contact angles for the nanoparticle embedded membranes (UF-Al2O3 and UF-LTL) and the control membrane (UF-C) were 57 degrees, 40 degrees and 66 degrees, respectively. Owing to the higher surface hydrophilicity, both UF-Al2O3 and UF-LTL demonstrated a higher filterability than UF-C. Biofouling was inhibited on both UF-Al2O3 and UF-LTL, indicated by the lower Pseudomonas aeruginosa biofilm formation rate. Further investigation showed that both UF-Al2O3 and UF-LTL exhibited a high anti-adhesion efficiency to both Escherichia coli and P. aeruginosa, but no bacteriocidal effect on E. coli. The anti-biofouling ability of UF-Al2O3 and UF-LTL mainly benefited from the anti-adhesion ability attributed to the embedded nanoparticles. The improved anti-adhesion ability could not be simply explained by the enhanced hydrophilicity. (C) 2015 Elsevier B.V. All rights reserved.