The rates of overweight and obesity are increasing worldwide in both developed and developing countries. Obesity is a major public health problem as it is associated with many diseases, including diabetes, hypertension, dyslipidemia, atherosclerosis, and some types of cancer. Breast cancer is a malignancy in which both the risk of development and the prognosis are negatively impacted by the obese state. The precise mechanisms pathophysiologically linking obesity and cancer are still under investigation. The biological basis for these associations includes both systemic and local tissue effects and white adipose tissue inflammation appears to be a critical component. A comprehensive understanding of the mechanisms linking obesity, inflammation and cancer may provide an opportunity for the development of strategies to attenuate the negative impact of obesity.