An improved analytical procedure is proposed for the determination of total actual acidity (TAA) in acid sulfate soils. The proposed method involves the use of a superior extracting solution, 0.5 M BaCl2, instead of the 1 M NaCl used by Konsten et al. (Konsten CJM, Brinkman R, Andriesse W. A field laboratory method to determine total potential and actual acidity in acid sulfate soils. In: Dost H, editor. Selected papers of the Dakar Symposium on Acid Sulfate Soils. Wageningen: ILRI Publication 44, 1988:106-134.) and improved experimental design to obtain correction factors for calculating TAA. The introduction of a multi-choice procedure also enables increased accuracy of analytical results to be obtained if more accurate TAA estimation is required.