Cancer is the third main cause of death in Iran. This report was provided for explaining most common cancers in Iranian Women. The National Cancer Registry reports from 2003 to 2006, pathologic based cancer registry reports from all of provinces of Iran. The age-standardized incidence rate of cancers was 56.80, 75.15, 6.18, 102.43 per 100 000 among females in 2003, 2004, 2005, 2006, respectively. The male to female standard ratio was 1.12. The most common cancer among women was breast cancer. The cancer registration system, is the main tool of management and control of cancers and such important information source is not only necessary for epidemiologic studies of the illness, but also for planning and forecasting the events, measuring the accuracy of the studies, and the effects of medical interventions. Without a cancer registry with defined standards, we may not be able to formulate, execute, and observe any cancer control plan. According to the results, breast cancer is the most common cancer in Iranian females. Therefore, breast cancer screening should be start in Iran.