This paper presents a new image-guided prostate biopsy system under development. The system features a 3-D prostate cancer distribution atlas and new biopsy protocols optimized based on the cancer atlas using a nonlinear integer programming approach. Both the cancer atlas and the optimal protocols are being dynamically registered and superimposed onto the trans-rectal ultrasound images during live-patient biopsy procedures. Clear visual guidance will be provided to the physicians by color-coded spots on top of the ultrasound images, which represent best possible targets for biopsy. Clinical test will be performed to evaluate the system.