A sequential extraction procedure is described for quantifying nine organic fractions (soluble fats, oils, and waxes; soluble carbohydrates; soluble phenolics; total hot‐water‐solubles; holocellulose; a‐cellulose; hemicellulose; lignin; and acid‐soluble carbohydrates) in highly organic soils, such asSphagnum‐derivedpeat. We present data indicating the procedure is accurate, if and only if corrections for ash concentrations of residual peat are made after each step of the extraction procedure, and with a high degree of precision (standard errors for each fraction average 4.5% of the fraction mean value).