The employment of several methods in the determination of cation exchange capacity of soils is discussed. The methods utilized were the direct ammonium acetate method and two indirect methods, in which the exchangeable bases were added to the exchange acidity extracted from soils, respectively with neutral calcium acetate and barium chloride buffered at pH 8.2 with triethanolamine. Though different results were obtained, excellent relationships were found between the calcium acetate method and the procedures with ammonium acetate and barium chloride, as well as two simplifications of the calcium acetate method.