Impressive reductions in breast cancer mortality have been demonstrated through regular screening programs using mammograms and clinical breast examinations. Nevertheless, only a small proportion of American women obtain annual mammograms. The US HEALTHCHECK breast cancer screening program offered free breast cancer screening to age-eligible members of a Health Maintenance Organization. Subscribers were mailed packets of materials and asked to return a Breast Risk Assessment Form to determine their eligibility to receive a free mammogram. This study was conducted to assess why women did or did not return a Breast Risk Assessment Form. Brief telephone interviews were conducted with a random sample of compliers and noncompliers (n = 502). Women who complied by returning the Risk Assessment Form said more frequently that they were unlikely to get breast cancer, were older, and more likely to have read the materials and to have rated them positively than women who did not return the Risk Assessment Form.