The cation exchange capacity (CEO of soil determined by the methods of IN calcium acetate at pH 7.0, IN amonium acetate at pH 7.0 and triethanolamine buffered barium chloride at pH 8.2 were compared with results obtained by the SMP buffer method to determine (H + Al) added to the sum of bases to calculate the CEC. The correlations between the results, obtained by the different methods, of (H + Al), CEC, and percent base saturation and the SMP were high. Due to this fact and the operational advantages, the SMP method showed to be adequate for CEC determination in routine analysis.