In this study, a vanadium (III) complex bearing a salicylaldiminato ligand of the general formula [RN=CH(2,4-(Bu2C6H2O)-Bu-t)]VCl2(THF)(2), where R=2,6-(Pr2C6H3)-Pr-i, was used as a catalyst. Titanium dioxide doped with iron nanofillers was synthesized by a sol-gel process and used to investigate the effect of nanofillers on ethylene homopolymer and ethylene/propylene copolymer properties. To the best of our knowledge, this is the first time titanium dioxide doped with iron has been used as a nanofiller in ethylene polymerization and ethylene/propylene copolymerization using a vanadium complex with methyl aluminum dichloride as a cocatalyst. Besides catalyst activity, the molecular mass (M-w) of the obtained polymer, molecular mass distribution, copolymer composition, crystallinity, and thermal characteristics of polyethylene and polyethylene/polypropylene nanocomposites were investigated.