The utilization of ferric chelates for the oxidation of the total reduced sulfurs quartet (H(2)S, CH(3)SH, CH(3)SCH(3), CH(3)S(2)CH(3)) is one of the various approaches to mitigate the emission of these airborne pollutants from Kraft pulp-mills' effluents. Oxygen solubility in iron chelate solutions is one important parameter in designing and modeling the regeneration process from ferrous to ferric chelates. Because of the interfering oxidation occurring in Fe(II) chelate solutions, the solubility of oxygen in aqueous solutions in which the gas does not react (Fe(III) complexes of trans-1,2-cyclohexanediaminetetraacetic acid (CDTA)) was studied at pressures near atmospheric pressure and temperatures from (293 to 313) K. New experimental solubility results over a chelate concentration ranging from (38 to 124) mol(.)m(-3) and pH values of 3 and 7.5 are reported. From the Henry's law constants and their variation with temperature, the standard thermodynamic solution properties of oxygen in these solutions were obtained.