Prostate cancer is the most common cancer in men of the Western world. Lifestyle, diet, environment and genetic factors (e.g., deregulations of the Wingless (Wnt) signaling pathway) promote the transformation of healthy prostatic epithelium to malignant tissue. Due to the high prevalence and slow progression of prostate cancer, primary prevention appears to be an attractive strategy for prostate cancer eradication. During the last several decades, curcumin (diferuloylmethane), a natural compound extracted from the root of turmeric (Curcuma longa), has been described as a potent chemopreventive agent against transformation. It exhibits anti-inflammatory, anti-carcinogenic, anti-proliferative, anti-angiogenic and anti-oxidant properties in various cancer cells. This study was designed to identify proteins involved in curcumin anti-cancer activity in androgen-dependent and -independent human prostate cancer cells using a two-dimensional difference in gel electrophoresis (2D-DIGE) proteomic approach. Our approach allowed us to discover 425 proteins that are differentially expressed after curcumin treatment. Identification of selected proteins by MALDI-TOF-MS led to the conclusion that curcumin modulated proteins that are implicated in protein folding (such as heat shock protein PP2R1A; RNA splicing proteins RBM17, DDX39; cell death proteins HMGB1 and NPM1; proteins involved in androgen receptor signaling, NPM1 and FKBP4/FKBP52) and that this natural compound could have an impact on miR-183 and mi-R141 expression. Taken together, these data support the hypothesis that curcumin is a chemopreventive agent in that it modulates the expression of proteins that potentially contribute to prostate carcinogenesis.