Breast cancer is among the most common malignant tumors all around the world. For years themedical community is trying to find a way to treat carcinoma. Investigating new anticancertreatments with greater efficacy and fewer side effects is still a significant challenge of the medicalsociety. Curcumin, a hydrophobic polyphenol derived from rhizome of Curcuma longa had beenappreciated for many therapeutic effects in traditional medicine, as well as recent investigations.Several studies have shown various activities for it; such as anti-hyperlipidemic and metabolicsyndrome, anti-inflammatory, antioxidant, immunomodulatory and neuroprotective properties. Ina few clinical trials the anti-cancer effect of curcumin has been seen, especially as achemoprevention agent in colon and pancreatic cancer, cervical neoplasia and breast metaplasia.The anticancer effects of curcumin may be mediated through the different biological pathway,including anti-proliferation, enhancing apoptosis, cell cycle arrest and antioxidant and antiangiogenicproperties. It had been indicated that curcumin may modulate several molecular targetand receptor affinity, including transcription factors (signal transducer and activator oftranscription 3, and nuclear factor-κB), receptors (estrogen receptor, interleukin 8, and humanepidermal growth factor receptor), kinases (extracellular-signal-regulated kinases, and Januskinase), cytokines (tumor necrosis factor, interleukin, chemokine (C-X-C motif) ligand -1 and 2),enzymes (Matrix metalloproteinases, and inducible nitric oxide synthase), growth factors(Epidermal growth factor), oncogenes (microRNA, DNA, histone, and mitochondria). In addition,curcumin may act as a chemosensitizer in multi-drug-resistant breast cancer cells and curcuminsupplementation with conventional chemotherapeutic agents could increase their efficacy as wellas reducing drug toxicity. Conclusion: Many basic in vivo and in vitro studies introduced thechemopreventive and anti-breast cancer effects of curcumin via modulation various biologicalpathways (cell signaling and gene expression). However, there are few standard clinical trials forevaluating those basic beneficial effects. In addition, clinical trials showed that the systemicbioavailability of oral administration of this safe medicinal agent is relatively low which reduced itspotential therapeutic effects. Therefore, the more standard clinical trial with curcuma longa (withdetermined curcumin content) or curcumin supplementation is needed to suggest the plant as aninexpensive potential biological adjuvant therapy in breast cancer.