Excluding skin cancer, prostate cancer is the most common cancer in North American men and causes 9% of male cancer-related deaths. Prostate cancer is rare in men younger than 50 years of age, and the incidence rises rapidly with each subsequent decade. The main risk factors for prostate cancer are family history, age, and race, as it occurs more commonly in black men than white men. Although prevalent, prostate cancer has a natural history that is heterogeneous and not well understood. Prostate cancer may progress slowly and is often not life threatening, or it may be more aggressive, resulting in greatly diminished long-term survival. The optimal treatment for patients with prostate cancer, particularly those with localized disease, is a controversial issue. The alternatives are watchful waiting or a variety of active treatments that may result in potentially serious complications. Although many older patients with less aggressive tumors will not die of prostate cancer but from other causes, watchful waiting is difficult for many patients to accept. Screening for prostate cancer can be performed using digital rectal examination (DRE), transrectal ultrasound (TRUS), or prostate-specific antigen (PSA); however, there is also controversy over the clinical benefits of screening. This is because the harms of overtreatment and overdiagnosis may outweigh the benefit of reduced prostate cancer mortality.