Solubility data are given for calcium sulfate dihydrate in the system CaCl(2)-MgCl(2)-KCl at the temperature range of (348.15 to 371.15) K and in ranges of concentrations up 3.86 m CaCl(2), 1.17 m MgCl(2), 0.27 m KCl, and their admixture by using a dissolution method. The calcium ion exhibits the common ion effect on the solubility of calcium sulfate dihydrate. The magnesium ion augments the solubility of calcium sulfate dihydrate in the investigated concentrations by stable MgSO(4)degrees ion pair formation. Potassium influences on the solubility of calcium sulfate dihydrate are found to be a salt effect by changing the activity coefficients of the calcium ion and sulfate ion. The temperature has a positive effect on the solubility both in magnesium chloride and potassium chloride solutions. There are two sharp falls. One is between (359.15 and 363.15) K in calcium chloride solution, and the other is at a potassium ion concentration of 0.108 mol.kg(-1) in its solution. The common ion effect is the main factor on the solubility of calcium sulfate dihydrate in the mixed salts solution. The measured solubilities are also compared with available literature studies, and the relationship with ionic strength is discussed empirically.