One hundred ninety-seven women over 40 years old and not adhering to national guidelines for screening mammography viewed persuasive messages varying in attributional emphasis (internal, external, or information-only). Internal attributions of responsibility for health-promoting behavior were expected to motivate the greatest change in women's attitudes and behaviors in relation to breast cancer and mammography. Attitudes about breast cancer and mammography were measured immediately and 6 months after the presentation. Twelve months later, women who viewed the internal message were more likely to have obtained a screening mammogram than women assigned to the other 2 conditions. The attributions of responsibility encouraged by the persuasive messages were associated with whether viewing the presentation led to behavior change.