Prostate cancer is the most commun cancer in men in the western world. Lifestyle, diet and environmental as well as genetic factors (e.g. disregulations of the Wingless (Wnt) signaling pathway) promote the malignant transformation of healthy prostatic epithelium. Due to the high prevalence and the slow progressive development of prostate cancer, primary prevention appears as an attractive strategy to eradicate prostate cancer. During the last decades, chemoprevention using non-toxic natural or synthetic compounds appeared to play an important role in cancer prevention and treatment, alone or in conjugation with usual drugs. Curcumin (diferuloylmethane), a major component of turmeric (Curcuma Longa), is one of the most well studied natural compounds characterized for its anti-inflammatory, anti-carcinogenic, anti-proliferative, anti-angiogenic and anti-oxidant properties. With this in mind, we studied the anti-proliferative potential of curcumin in prostate cancer. We demonstrate here that curcumin has the same intracytoplasmic localization in all prostate cancer cells tested. Interestingly, the androgen sensitive cells appear more sensitive to curcumin treatment than the androgen independent ones. We report that curcumin has an impact on the proliferation of androgen sensitive prostate cancer cells through the induction of cell cycle arrest in G2/M. By the same way, curcumin was shown to affect the Wnt signaling pathway highly implicated in prostate cancer cell proliferation. We observe a modulation of the expression of proteins implicated in this pathway, that leads to a decrease of the Wnt (beta-catenin/Tcf-4) transcriptional activity resulting in the decrease of Wnt target gene expression.Altogether our results suggest that curcumin could be considered as an interesting chemopreventive agent for early but not for late, metastatic prostate cancer.