Abstract: A method for the determination of common organochlorine pesticides (OCPs) and polychlorinated biphenyls (PCBs) in groundwater by gas chromatography (GC) was developed. The method provides the detection limits of lower than 2.21 ng/L for OCPs, 5.20 ng/L for PCB 1 and lower than 1.30 ng/L for other target pollutants. The recoveries for most of the OCPs and PCBs were 63.5%~110.2% with precision of 2.2%~17.3% RSD (n=5) and the recoveries of the pollutants in practical samples were 87.34%~133.76% except for endrin. The method provides the advantages of good stability and reproducibility, simple sample preparation and has been applied to the determination of OCPs and PCBs in groundwater samples.