The imaging, diagnosis, and successful treatment of prostate cancer (PCa) continue to be a challenging problem and it is estimated that 1 out of 6 men will be diagnosed with the disease during their lifetime, making this disease the second leading cause of death among men. Therefore, developing more effective therapeutic agents against advanced PCa that allows for simultaneous therapy and monitoring of tumor growth are equally important. Particularly, theranostic (dual therapy and diagnostic) agents are targeted to the disease regimes that allow delivery of therapeutic agents in high concentrations to PCa, while monitoring of drug localization to the tumor. The concept of a nanoparticle-based therapeutics is ideal as a single agent that could deliver a drug and imaging agent to the prostate tumor via recognition of surface receptor markers highly expressed on the tumor cells. In this presentation, we will discuss about a new method of targeting prostate cancers. We report for the first time that the use of glutamate ligand-decorated and taxol anti-cancer drug encapsulating magnetic nanoparticles to target PSMA-bearing PCa cells. Prostate Specific Membrane Antigen (PSMA) is over-expressed on the surface of LNCaP prostate cancer cells and successfully targetd by glutamate-decorated magnetic nanoparticles. Results showed more than 80% LNCaP cells were death after 24 h incubation of the drug-carrying nanoparticles. No apoptosis was observed in PC-3 cells due to the absence of PSMA receptors. These results were further confirmed using optical microscopy and magnetic resonance imaging technologies.