The aqueous solubilities of selected polychlorinated dibenzo-p-dioxins (PCDDs) and polychlorinated dibenzofurans (PCDFs), including their non-chlorinated compounds, were measured at 25 degrees C using the generator column method to prepare their saturated aqueous solutions. Newly measured aqueous solubility data are reported for 1,2,3,4,6,9-hexachlorodibenzo-p-dioxin and octachlorodibenzofuran. Additionally, changes in solubilities of dibenzo-p-dioxin, 2-monochlorodibenzo-p-dioxin, 2,7-dichlorodibenzo-p-dioxin, dibenzofuran, and 2,8-dichlorodibenzofuran were studied in sodium, potassium, and calcium chloride solutions at various concentrations of the individual salts. From the measured solubility data, the salinity parameters, known as the Setschenow constants, were derived for the selected PCDDs and PCDFs and are reported here for the first time.