Vaccines targeting infections with hepatitis B virus, a risk factor for hepatocellular cancer, and human papillomavirus, a risk factor for cervical cancer, are considered major clinical cancer chemoprevention successes. Molecularly targeted agents can prevent breast cancer (raloxifene and tamoxifen), colorectal adenomas (celecoxib), and prostate cancer (finasteride). Nevertheless, the broad translation of chemoprevention to the clinic is not yet a reality. Continuing research of molecular targets promises to expand the reach of chemoprevention and to personalize it as well.