Prostate cancer is the most common malignancy in men and continues to be a major public health problem. Imaging of prostate cancer remains particularly challenging owing to disease heterogeneity. Molecular imaging can provide unprecedented opportunities for deciphering the molecular mechanisms that are involved in the development and natural progression of prostate cancer from a localized process to the hormone-refractory metastatic disease. Such understanding will be the key for targeted imaging and therapy and for predicting and evaluating treatment response and prognosis. In this article, we review briefly the contribution of multimodality molecular imaging methods for the in vivo characterization of the pathophysiology of prostate cancer.