The study aimed to assess associations between Health Belief Model variables, stages of change, and participation in mammography for early detection of breast cancer in a sample of Iranian women. A total of 414 women, aged 40 to 73 years, were recruited by random sampling. The study took place in the winter of 2007, using a self-report questionnaire and structured interviews, designed to measure the five Health Belief Model constructs and stages of adoption for mammography. The study indicated that 45.8% of the women were in the pre-contemplation and contemplation stages of a mammogram, and 29% of participants reported having had at least one mammogram. Screening behavior was associated with older age, familial history of breast cancer, history of breast disease, health insurance coverage, and living in an urban area. Furthermore, the perceived susceptibility to breast cancer, perceived benefits and barriers for mammography, and cues to action variables defined by the Health Belief Model were four factors related to having a mammogram. The study concludes that health care professionals must provide women with more fear appeals that outline vulnerability to developing breast cancer, remove cognitive barriers to seeking mammography, and apply effective guidance on the participation of women in breast cancer screening programs.