The development of biomarkers for prostate cancer screening, detection, and prognostication has revolutionized the management of this disease. Prostate-specific antigen (PSA) is a useful, though not specific, biomarker for detecting prostate cancer. We review the literature on prostate cancer biomarkers, including serum markers (PAP, tPSA, fPSA, proPSA, PSAD, PSAV, PSADT, EPCA, and EPCA-2), tissue markers (AMACR, methylated GSTP1, and the TMPRSS2-ETS gene rearrangement), and a urine marker (DD3PCA3/UPM-3). Future research should focus on validation of already existing biomarkers and the discovery of new markers to identify men with aggressive prostate cancer.