Background: Prostate cancer is second most common cancer in men overall in the world, whereas it is the third most common cancer in men and the sixth most common cancer in Iran. Few studies have been conducted on the epidemiology of prostate cancer in Iran. Since ethnicity of Iranian men is different from Asian people and given the epidemiologic and demographic transition taking place in Iran, this study aimed to investigate trends of incidence and morphology of prostate cancer during 2003 - 2008 in the country. Materials and Methods: Data were collected retrospectively reviewing all new prostate cancer patients in the Cancer Registry Center of the Health Deputy for Iran during a 6-year period. Also carcinoma, NOS and adenocarcinoma, NOS morphology were surveyed. Trends analysis of incidence and morphology was by joinpoint regression. Results: During the six years a total of 16,071 cases of prostate cancer were recorded in Iran. Most were adenocarcinomas at 95.2 percent. Trend analysis of incidence (ASR) There was a significant increase incidence, with annual percentage change (APC) of 17.3 and for morphology change percentage trends there was a significant decrease in adenocarcinoma with an APC of -1.24. Conclusions: Prostate cancer is a disease of older men and the incidence is increasing in Iran. The most common morphology is adenocarcinoma this appears to be decreasing over time. Due to the changing lifestyles and the aging of the population, epidemiological studies and planning assessment of the etiology of prostate cancer and its early detection are essential