Abstract: In this work yttrium oxide (Y2O3) nanocrystallites were synthetized by mean of sol-gel method using two different precursors. The raw materials were: yttrium nitrate, yttrium chloride and methanol as solvent. In order to promote the oxygen vacancies P123 poloxamer was incorporated. All as synthetized system were heat treated at temperatures from 700 ºC to 900 ºC, the systems at 900 ºC were prepared with and without P123 at two different molar ratios of P123:Y (1:1, 2:1). The Infrared Spectroscopy results revealed characteristic absorption band of Y-O vibrations of Y2O3 matrix. The structural phase was analyzed trough X-ray Diffraction, the diffractogram showed the cubic phase in all systems. The major intensity of the diffraction peak was presented for the system prepared from yttrium chloride incorporating P123 in a molar ratio of P123:Y, 2:1 at 900 ºC. The range of the crystallites sizes was determined by Scherer equation obtaining them of 26-32 nm. Antioxidant properties were estimated by DPPH and ABTS assays; the results are presented and discussed.