Abstract: Gas chromatography with sample pretreatment by automatic head-space solid phase micro-extraction was applied to the determination of 2,4,6-trichlorophenol (TCP) and pentachlorophenol (PCP) in drinking water. The water sample (10.0 mL) was added to a 20 mL-head-space flask in which 0.5 mL of 0.1 mol·L-1 HCl and 4.0 g of NaCl were added previously. After capping the flask tightly, the polyacrylate extractor (85 μm) was inserted into it and shaked at the rate of 500 r·min-1 at 60 ℃ for 40 min to extract the chlorophenols, which were then desorbed and determined by GC. HP-5 capillary column was used for separation with programmed temperature elevation from 40 ℃ to 280 ℃. Flow-rate of carrier gas taken was 3 mL·min-1. Linear relationships between values of peak area and mass concentration of TCP and PCP were obtained in the ranges within 55 μg·L-1 and 12 μg·L-1 respectively, with detection limits (3S/N) of 0.15 μg·L-1 (for TCP) and 0.13 μg·L-1 (for PCP). Tests for recovery and precision were made by addition of standards at 3 concentration levels, giving results of recovery in the range from 90.0% to 112.8%, and RSD′s (n=6) from 3.0% to 4.9%.