Solubilities of potassium chloride (KCl) and sodium chloride (NaCl) in aqueous systems containing the ionic liquid 1-butyl-3-methylimidazolium chloride ([Bmim]Cl) were determined by cloud-point measurements using the laser beam scattering method in a temperature range of (298.15 to 343.15) K at atmospheric pressure. The solubility data were correlated and calculated with the Pitzer model modified by Harvie and Weare. The interaction parameters of the mixed-electrolyte solution were obtained using experimental results. It was found that the addition of [Bmim]Cl leads to salting-out, triggering a marked decrease of salt solubility in the aqueous solutions. The results also show that [Bmim]Cl has different salting-out ratios on KCl and NaCl in the mass-fraction range of w([Bmim]Cl) = (0.025 to 0.20). It is also shown that the modified Pitzer model gives a satisfactory prediction for the solubilities of KCl and NaCl in aqueous systems containing ionic liquid [Bmim]Cl.