Abstract: OBJECTIVE To develop a method for the determination of polychlorinated biphenyls (PCBs) in traditional Chinese medicine by GC-MS/MS. METHODS PCBs in traditional Chinese medicine were extracted by ultrasonic and purified by sulfuric acid, internal standard method for quantification; and then determined in multiple reaction monitoring (MRM) mode with EI source. RESULTS The method showed good linearity when the concentration of 18 PCBs were within 0.5-50.0 ng·L^-1, with the correlation coefficient (r) within 0.999 8-1.000 0. The limits of detection were within 0.013-0.080 μg·kg^-1. The limits of quantification were 0.054-0.328 μg·kg^-1. The average recoveries were within 106.7%-118.7% at the spiked levels of 2 μg·L^-1, within 93.5%-114.7% at the spiked levels of 5 μg·L^-1 and within 89.9%-115.6% at the spiked levels of 10 μg·L^-1. The relative standard derivations were within 1.6%-8.0%, 2.7%-4.6% and 1.0%-3.1%, respectively. CONCLUSION The method for determination of PCBs in traditional Chinese medicine was rapid, simple, sensitive and accurate. It is suitable for determination of 18 PCBs in traditional Chinese medicine.