An analytical method was developed for a determination of PCBs and chlorinated pesticides, and a screening of environmental pollutants using a tandem quadrupole mass spectrometer (GC/MS/MS). The GC/MS/MS was operated in simultaneous scan and MRM measuring (scan/ MRM) to reduce an analysis time. The developed method was applied to river water samples. PCBs were selectively detected and determined from the MRM data and 84 pollutant compounds were semi-quantitated from the scan data. The results demonstrated that the developed method is effective for the target analysis of PCBs and chlorinated pesticides, and the screening of environmentalpollutants by only one analysis.