CO₂ mineralization is a method of sequestering CO₂ in the form of carbonated minerals. Brine discharged from seawater desalination is a potential source of Mg and Ca, which can precipitate CO₂ as forms of their carbonate minerals. The concentration of Mg and Ca in brine are twice those in the seawater influent to desalination process. This study used a cycle for CO₂ mineralization that involves an increase in the pH of the brine, followed by CO₂ bubbling, and, finally, filtration. To the best of our knowledge, this is the first time that non-synthesized brine from a seawater desalination plant has been used for CO₂ mineralization. The resulting precipitates were CaCO₃ (calcite), Mg₅(CO₃)₄(OH)₂·4H₂O (hydromagnesite), and NaCl (halite) with these materials being identified by X-ray Diffraction (XRD), Fourier transform infrared (FTIR) and thermo gravimetric-differentail thermal Analysis (TGA)-DTA. Despite the presence of Ca with Mg in brine being unfavorable for the precipitation of Mg carbonate, Mg reacted with CO₂ to form hydromagnesite at a yield of 86%. Most of the Ca formed calcite, at 99% yield. This study empirically demonstrates that brine from seawater desalination plants can be used for CO₂ mineralization.