Benomyl is used as a protective and eradicant fungicide. It is effective against a wide range of fungi that affect field crops, fruits, nuts, ornamentals and turf. Benomyl was known to endocrine disrupter, and easily decomposed to carbendazim. In this study, benomyl was analyzed for the 43 samples of river water, 35 samples of soil and 11 of sediments in Korea. It had been detected most of water samples. Liquid-liquid extraction with methylene chloride was used for water samples and sonication extraction method was used for soils and sediments with methanol as a extracting solvent. And then the extracts was derivatized by methyl iodide and analyzed by GC/MSD. Recovery and relative standard deviation of the benomyl in spiked water samples are 80.7% and 8.7% respectively.