Introduction: Design and implementation of screening programs in each country must be based on
epidemiological data. Despite the relatively high incidence of CRC, there is no nationwide comprehensive program
for screening in Iran. This study was designed to investigate national CRC data and help to determine guidelines
for screening. Methods: Incidence data used in this study were obtained from Iranian annual of National Cancer
Registration report. Age standardized rates (ASR)were calculated using world standard population and were
categorized by age, sex, anatomic subsite and morphology of tumor. Data were analyzed using SPSS.V.13 and
Open Source Epidemiologic Statistics for Public Health software (OpenEpi v.2.3.1). Results: A quarter of cases
were less than 50 years of age. The majority of tumors were detected in the colon. The overall ASR in the four
years period was 38.0 per 100000 and was higher for men compared women (P<0.05). Incidence rate of colorectal
cancer increased with age. Conclusion: Results of present study indicated that incidence of colorectal cancer
is relatively high in Iran. Incidence of CRC in people under 50 years and in rectum were reported higher than
other countries that related etiologic factors should be investigate in further studies. According to the increasing
of ASR after age 50 years, it seems that onset of screening at age 50 would be appropriate.