The solubility and stability of nesquehonite (MgCO3 center dot 3H(2)O) in mixed solutions (NaCl + MgCl2, NH4Cl + MgCl2, LiCl, and LiCl + MgCl2) were measured by using a classic isothermal dissolution method over the temperature range of (298 to 308) K. The concentration investigated for all salts was up to 0.2 mol.dm(-3) NaCl, 1.5 mol.dm(-3) NH4Cl, 0.6 mol.dm(-3) MgCl2, and 1.5 mol.dm(-3) LiCl at ambient temperature. The solubility of MgCO3 center dot 3H(2)O phases in all the cases investigated was found to increase with the temperature increment. The comparison of solubility in MgCl2 solutions and NaCl + MgCl2, NH4Cl + MgCl2, and LiCl + MgCl2 mixed solutions has been investigated. XRD and SEM examination of the equilibrated solids showed that nesquelionite in all cases is stable in the temperature range of (298 to 308) K.