Liquid-phase microextraction (LPME) followed by gas chromatography (GC) coupled with an electron capture detector (ECD) was applied for the analysis of pentachlorophenol (PCP) in aqueous samples. After alkalization with Na2CO3 solution, PCP was acetylated with acetic anhydride. The pentachlorophenyl acetate derivative was then extracted with n-hexane by LPME. 1.5 μL organic drop exposed to the aqueous sample solution at 15°C for 5 min, stirring rate at 100 r/min was chosen as the optimum extraction condition. Under this condition, LPME provided a very simple, fast and solvent-less procedure to collect PCP from aqueous sample for GC determination. The linearity of LPME/GC-ECD for PCP in distilled water was investigated at the range of 2–200 μg/L with a coefficient of correlation 0.998. The repeatability of this method was determined at the level of 50 μg/L with the average of relative standard deviations (RSDs) 7%. Detection limit was obtained at less than 0.5 μg/L levels. When LPME/GC-ECD was applied to the determination of PCP in municipal sewage, the average of relative recoveries and RSDs were 70% and 6.5%, respectively.