OBJECTIVE: Most studies of dietary change during aging have focused on maintaining adequate intake by impaired elderly, and little is known about factors affecting dietary change for preventive purposes in older individuals. The purpose of this exploratory study was to determine the major behavioral influences on older women's adherence to a dietary fat reduction intervention. METHOD: A diverse sample of 92 women aged 55 to 80 was recruited from two East Coast sites of the Women's Health Initiative. All the women were participating in the dietary modification arm of WHI, had received the same dietary instruction, and were in the maintenance phase of the intervention. The women were classified by nutritionists as adherent or nonadherent to a diet limiting fat intake toRESULTS: Adherent women were more likely to report assertiveness, a lifelong commitment to reduced dietary fat, satisfaction with their lifestyle changes, and having applicable knowledge and skills. Nonadherent women reported more difficulty resisting negative emotions and prior food preferences and habits; they were also more concerned about negative responses from others. CONCLUSIONS: Enhancing adherence of older women to a dietary fat reduction program will require shifting priorities away from conforming to social pressure and using high-fat foods for personal satisfaction and moving toward enhancing motivation and commitment to long-term health.