Nutrition is apparently a major risk factor for the development and progression of prostate cancer. Based on experimental studies and epidemiologic data mainly from case-control studies or cohort studies, there is strong evidence that reduction of the total energy consumption, a diet comprising less than 30% fat, and increased intake of phytoestrogens, vitamins D and E and selenium could yield a decreased prostate cancer incidence. Furthermore, some of these measures appear to have antitumoral capacity even in the presence of the disease. These observations have provided a rationale to forward large prospective trials on dietary interventions to prove the efficacy of the concept and further delineate the correlation between nutritional compounds and prostate cancer risk. These chemoprevention trials are either aiming a reduction prostate cancer incidence or a decrease in tumor progression. Depending on the study design, large numbers of individuals need to be enrolled and long follow-up intervals are required thus making such trials highly complex and cost-intensive. However, regarding the potential relevance of chemoprevention on public health, further efforts to identify nutritional factors affecting prostate cancer growth are warranted.