Abstract: A gas chromatography-mass spectrometry (GC-MS) method for the simultaneous determination of 39 pesticides residues in water and sediments was developed. The water sample was extracted with ethyl acetate and was passed through a column loaded with anhydrous sodium sulfate. The sediment sample was ultrasonically extracted with acetonitrile and then cleaned up with N-propyl ethylenediamine (PSA) and graphitized carbon black (GCB). The pesticide residues were detected in selected ion monitoring (SIM) mode and was quantified by external standard method. The results showed that the linear relationship of the 39 pesticides was good with coefficient of determination (R²) > 0.9950. The recoveries of pesticides spiked in blank water samples at three levels (0.25, 0.5, and 5.0 µg/L) were in range of 72%-111%, with the relative standard deviation (RSD, n = 5) of 1.1%-10%. The limits of detection (LODs) were 0.02-0.06 μg/L and the limits of quantification (LOQs) were 0.04-0.18 μg/L. The average recoveries of pesticides spiked in blank sediment samples at three levels (5.0, 20.0, and 100.0 µg/kg) were in range of 65%-119%, with the RSD of 2.1%-12%. The LODs were 0.7-1.5 μg/kg and the LOQs were 2.1-4.3 μg/kg. The established method is sensitive, accurate, and reliable. It is suitable for the detection of 39 target pesticides in water and sediments.