In this work, dispersive liquid liquid microextraction and gas chromatography was used for determination of monochloroacetic acid (MCAA), dichloroacetic acid (DCAA) and trichloroacetic acid (TCAA) in water samples. Extraction is based on the rapid injection of mixture contain n-octanol as extraction solvent and acetonitrile as disperser solvent into sample solution. The cloudy solution was centrifuged immiediately after formation and finally extraction solvent was collected. Because of lower density of the solvent than of water, a new device was designed for collecting of extraction solvent from the solution. n -octanol was used as extraction and derivatization reagent. Experimental parameters, such as, amount of extraction and disperser solvent, the kind of disperser solvent, amount of salt, sample pH and extraction time were studied and optimized. The best of extraction efficiency was obtained using 75 µL of organic solvent, 1 mL of disperser solvent, 0 min extraction time, 150 gr/L of Na 2 SO 4 and 15% concentrated sulfuric acid in sample solution. Derivatization reaction was performed at 200 ? C during 2 min. Under the optimized condition, the method showed very low detection limits for DCAA and TCAA in the range 0.1- 0.02 µg/L and relative standard deviation were below 2.8%. The method has been successfully applied for the analysis of water samples.