Cr(III) hydrolysis in aqueous solution has been studied theoretically by means of density-functional method (DFT). All possible structures arising from different tautomers have been determined. The solvation energy has been calculated using the UAHF-PCM method. The hydrolysis reaction free energies have been calculated and compared with the available experimental data. The different hydrolysis species have distinct geometries and electronic structures. Improvement of theory level in calculating the electronic energy does not necessarily improve the calculated free energies in aqueous solution since the UAHF-PCM is a simple method that neglects specific interactions with the solvent. Therefore, it is important to have the correct balance between theory level used in the electronic properties calculation especially in the UAHF-PCM method. The PBE/TZVP/UAHF-PCM method has been found to calculate correctly the hydrolysis energies of Cr(III), deviating about 2.7 kcal/mol from experimental values.