Abstract: It has been well established that the incidence of PCa is lower in people living in the Mediterranean region compared to Western societies. This condition might be related to traditional Mediterranean Diet (MD) which has been used by this population. Recent reports have examined the MD on the risk of PCa, but the results are inconsistent. The purpose of the present study was to examine the relationship between adherence to MD and PCa risk in case-control study of Iranian men. The present study was conducted in Tehran (capital of Iran). Cases were cancer patients aged 40-78 years with incident, histologically confirmed PCa diagnosed not before 6 months of the interview. Controls were patients (43-71 years) who were sampled randomly from patients admitted to the same hospital as cases during the same time period (for acute, non-neoplastic conditions and not afflicted with diet-related chronic diseases). In total, 52 patients with PCa and 104 controls underwent face-to-face interviews by specifically trained professional interviewers (participation rate: 85%). We retrospectively assessed the association between MD and PCa in a population-based case-control study. Adherence to MD was associated with reduced risk of PCa. We found an inverse association between vegetables, fruits, dairy, fish, olives, legumes and nuts consumption with PCa risk.