[en] Background: Polychlorinated biphenyls (PCBs) are widespread highly resistant pollutants in the environment with potential adverse health effects on humans. The aim of the study was to compare PCBs contamination in women suffering from breast cancer with presumably healthy women. Methods: A gas-chromatography/mass-spectrometry method was used to identify and quantify seven PCBs congeners (IUPAC 28, 52, 101, 118, 138, 153,180) in blood from 60 cases of breast cancer and 60 age-matched healthy controls. Results: Cases and controls had similar risk profiles, except for menopausal status (respectively 82% vs. 65%, p=0.014). PCBs were detectable in 69.1% of the samples. Total blood level of PCBs was significantly different (p=0.012) in cases (7.08±7.51 ppb) and controls (5.10±5.15 ppb). The relationship between PCBs concentrations in serum and risk factor was mainly due to serum levels of PCB153, which were significantly higher in breast cancer women than in disease-free subjects (1.63±1.26 ppb vs. 0.63±0.78 ppb, p<0.0001), even after accounting for other potential risk factors. Conclusions: These results suggest that environmental exposure to PCBs may contribute to multifactorial pathogenesis of breast cancer.