A definitive cause for prostate cancer has not been established, however, there are risk factors.

The risk for prostate cancer increases with age as well as an increasing number of affected relatives (father, brother, uncle). The incidence is high in black Americans, Scandinavians but low in Asians. Smokers and workers exposed to cadmium are also at a higher risk. Other risk factors include a diet high in animal fat but low in fibers, and a previous vasectomy. High circulating levels of testosterone have also been noted in those with prostate cancer.

Sexual activity is not a risk factor.