Prostate cancer is the most common noncutaneous human malignancy, and the second most lethal tumor among American men. Thus, 241,000 US men are expected to diagnose with prostate cancer in 2012 while 28,000 are expected to die from this disease. Current standard of care require urologists to take 10-12 biopsies per patient during initial screening. Sensitivity and specificity of current prostate needle biopsies are 25% and 50%, respectively, since these biopsies are taken randomly without the knowledge of tissue morphology (whether tissue is malignant or not). Hence, random needle biopsies are subjected to serious sampling errors and often fail to provide the accurate grade and stage of the disease. Since as much as 50% of lethal cancers may remain undetected during initial biopsies, these patients are at risk of disease spreading beyond the prostate gland and even distant metastasis. Current prostate imaging modalities (e.g., TRUS, CT, MRI) do not provide any information regarding tissue morphology and have consistently failed to identify localized carcinomas contained within the prostate gland. Light interacts with biological tissue in a variety of ways (e.g., absorption, scattering, fluorescence). Optical properties of tissues are determined by their molecular composition and cellular morphology. As tissues undergo malignant growth, the optical properties change, offering the possibility of detecting disease state. Hence, optical spectroscopy methods can be used to determine whether human tissue is cancerous or not. Elastic scattering primarily probes morphological features (shape and size of cells, nucleus, intra-extra cellular architecture, etc.) and has proven to be sensitive to cancer grades while fluorescence signal depends on amounts of proteins, lipids, vitamins, etc., in tissue. Based on these spectroscopic principles, optical biopsy techniques have been developed to diagnose skin, esophageal, bladder, and colon cancers, but none available for prostate cancer. An optical biopsy needle has been developed by integrating an optical sensor at the tip of the inner needle of a standard clinical biopsy needle to obtain prostate biopsies. Optical sensor consist of eight 100 micron source fibers arranged in a circle with a single 200 micron center fiber to read the fluorescence signal from endogenous fluorophores in prostate tissue that include tryptophan, collagen, and NADH. Preliminary studies demonstrate prototype optical biopsy needle can separate prostate cancer from benign tissue with sensitivity and specificity of 84% and 96%, respectively.