Urologists routinely use the systematic sextant needle biopsy technique to detect prostate cancer. However, recent evidence suggests that this technique has a significant sampling error. We have developed a novel 3-D computer assisted prostate biopsy simulator based upon 201 whole-mounted step-sectioned radical prostatectomy specimens to compare the diagnostic accuracy of various prostate needle biopsy protocols. Computerized prostate models have been developed to accurately depict the anatomy of the prostate and all individual tumor foci. We obtained 18-biopsies of each prostate model to determine the detection rates of various biopsy protocols. As a result, the 10- and 12-pattern biopsy protocols had a 99.0% detection rate, while the traditional sextant biopsy protocol rate was only 72.6%. The 5-region biopsy protocol had a 90.5% detection rate. The lateral sextant pattern revealed a detection rate of 95.5%, whereas the 4-pattern lateral biopsy protocol had a 93.5% detection rate. Our results suggest that all the biopsy protocols that use laterally placed biopsies based upon the five region anatomical model are superior to the routinely used sextant prostate biopsy pattern. Lateral biopsies in the mid and apical zones of the gland are the most important.