Green liquor dregs (GLD) is an alkaline by-product from the paper and pulp industry with a pH between 10 and 14. Today most of the produced GLD in Sweden are landfilled. In order to increase the utilization, the environmental performance needs to be determined. Samples were collected from 16 mills at 3 different times approximately 6 months apart, totalling 42 samples. Leaching was performed in two sequential steps at an L/S ratio of 2 and 8 on wet samples corresponding to 25 g DM. The liquid phases were analysed for pH, electrical conductivity, alkalinity, anions and element concentrations. Leaching of sodium and potassium were as expected very high but leaching of calcium was low. Chromium, nickel, copper, cadmium and zinc leaches generally less than ≤5% of total concentrations. Sodium and potassium are present in GLD as easily soluble salts that are easily washed out. Calcium leaching is restricted by calcite solubility resulting in little effect on short time buffering capacity, however, in the long term calcium minerals will affect the buffering capacity. For nickel, copper, cadmium and lead there are some soluble salts present in the GLD but most of the elements are probably solubility controlled. Geochemical calculations indicated hydroxides as solubility controlling phases for at least copper and in some cases also for lead. Leaching of zinc is to some extent solubility controlled which is indicated by the fact that the soluble concentrations is similar for both L/S 2 and L/S 8. When comparing the leached concentrations from GLD with concentrations from mining waste there is an environmental benefit even if the GLD is not inert. In conclusion, GLD is well suited to be used for treatment of acidic mining waste instead of being landfilled in non-hazardous and hazardous landfills.