Rates of physical inactivity and poor nutrition, which are 2 of the most important modifiable risk factors for cardiovascular disease in women, are substantial. Even so, studies of interventions designed to improve lifestyle behaviors in women have been limited and often confined to particular geographical areas. To evaluate the effect of Choose to Move on increasing women's physical activity, improving their knowledge of heart disease and stroke, and improving their nutrition. A prospective, nonrandomized, 12-week educational intervention designed by the American Heart Association for women across the United States. Participants received a welcome kit and manual with weekly information about how to manage cardiovascular disease risk factors and how to build a support system for lifestyle change. Women (N = 23 171) aged 25 years or older were recruited by direct mail, the media, health care providers, and other means. Follow-up evaluations were returned from 6389 women at 2 weeks, 5338 at 4 weeks, 4209 at 8 weeks, 3916 at 10 weeks, and 3775 at 12 weeks. Participants self-reported their physical activity, diet, and knowledge about heart disease, stroke, and related symptoms. Ninety percent of the participants were white and 56% were aged between 35 and 54 years. Among the participants who completed the week 12 follow-up evaluation, the percentage who reported being active (at least moderate exercise > or =5 times per week or >2(1/2) hours per week for the past 1 to 6 months) increased from 32% at baseline to 67% at the program's end (P =.001). Participants currently limiting excess calories or fat increased from 72% to 91% at week 10 follow-up evaluation (P =.001). The proportion correctly identifying heart disease as the leading cause of death increased from 84% to 91% at week 10 follow-up evaluation (P<.001). Women who completed the Choose to Move program evaluation reported that they significantly increased their levels of physical activity, reduced their consumption of high-fat foods, and increased their knowledge and awareness of cardiovascular disease risk and its symptoms. This program provides an important model for public health, voluntary, and other health organizations of population-based, targeted low-cost self-help programs that support the Healthy People 2010 objectives for physical activity, nutrition, and cardiovascular health.