This International Standard specifies a method for the determination of the cation exchange capacity (CEC) and the content of exchangeable cations (Al3+, Ca2+, Fe2+, K+, Mg2+, Mn2+, Na+) in soils using a hexamminecobalt trichloride solution as extractant. NOTE As the pH of a soil suspension in the hexamminecobalt trichloride solution is close to the pH of the suspension in water, this method is considered to give the effective CEC, i.e. the CEC at the soil pH. This International Standard is applicable to all types of air-dried soil samples which have been prepared in accordance with ISO 11464. References and results of the comparison with other methods (barium chloride, ammonium acetate) are given in Annex A.