The purpose of this study was to identify the distribution of non-ortho and mono-ortho PCB congeners and homologues in adipose tissues and sera of women with breast cancer. The collected samples were 25 adipose tissues and 33 sera from women with breast cancer. The samples from the control group were 49 adipose tissues and 52 sera. The levels of three non-ortho and eight mono-ortho PCBs identified in adipose tissue and serum samples were determined by GC/MSD and GC/ECD analyses. Non-ortho and mono-ortho PCB congeners were more dominant in the control group than in the case group for serum samples. The Tetra-PCB and the Hexa-, Hepta-PCB were more dominant in tale and control groups, respectively. The level of PCB homologues in normal women was similar to that of the normal human milk samples. However, the levels of PCB homologues from breast cancer patients were almost same the level of sample from environment. As a result of this study, it is suggested that breast cancer could be related to environmental factors such as PCB level in stack gas and soil sample. More extended research should be to verify this result.