The traditional Soxhlet extraction of pentachlorophenol (PCP) from soil samples has been modified to allow a rapid and efficient extraction. The modified procedure includes a derivatization in situ of the soil sample during the extraction. The traditional Soxhlet extraction (TSE) was compared with Soxhlet extraction with in situ derivatization (SED). Two different mixtures of derivative reactives, trietylamine-acetic anhydride (TEA-AA) and pyridine-acetic anhydride (PYR-AA), were utilized. Under the same experimental conditions, the yields obtained by SED were considerably greater, almost four times, and the extraction time was shorter than that by TSE. Additionally, the extracts of soil samples derivatized in situ, can be directly quantified by gas chromatography, while the extracts obtained by the traditional method require derivatization before the gas chromatographic analysis. The modified procedure that is simpler, rapid, and more efficient, is presented as an alternative to the conventional one used in the PCP analysis