OBJECTIVE To evaluate changes in food sources of dietary fat made by participants in the Women's Health Initiative Low-Fat Dietary Modification Trial. DESIGN This study compares sources of dietary fat intake, estimated by a food frequency questionnaire, between intervention and control participants at baseline, 1 year (year 1) and 2 years (year 2) after randomization. The outcome measure was intake of fat in grams per day. Results are given on consumption of fat from six food groups and the intervention effect, defined as mean change in the intervention group minus the change in controls, controlling for baseline fat intake. PARTICIPANTS 5,004 intervention and 7,426 control postmenopausal women in 40 clinical centers across the United States. RESULTS At baseline, the major sources of fat were added fats, such as butter, oils, and salad dressings (25%); meats (21%); and desserts (13%). From baseline to year 1, the intervention group reduced fat by 24.3 g/day compared with the control group. Reductions came primarily from added fats (9.1 g/day), meats (4.6 g/day), and desserts (3.9 g/day). White people reduced added fats more than other race/ethnicity groups did, white and Hispanic people were more likely to reduce fat intake from milk and cheese compared with other groups, and Hispanics reduced fat from mixed dishes more than did other race/ethnicity groups (P<.05 for all). APPLICATIONS/CONCLUSIONS These data indicate that women in the Women's Health Initiative dietary change intervention made substantial changes in food choices. These results can facilitate future low-fat interventions, and also offer clinical applications, by identifying foods that may be refractory to change.