Dietary patterns play a role on prostatic diseases in association with genetic, behavioral, occupational and environmental ones. Data from reviewed literature provide evidences of a possible relationship between dietary habits and the incidence of prostate disorders, even if it is not enough to justify a widespread adoption of new dietary habits. In this review the role of dietary patterns, including the use of supplements, in the prevention and treatment of the most frequent and known prostatic diseases, benign prostatic hyperplasia (BPH) and prostate cancer (PC) was analyzed. A limited number of well designed trials were identified in which diet and dietary supplement intervention appeared to slow disease progression. Although conclusive evidences are limited, the current data suggest that a diet low in total calories and fat, high in vegetables and fruits and that body weight control could be possibly effective in preventing prostatic diseases. On the other hand care must be taken to ensure that over-consumption of dietary supplements does not occur because it may be harmful.