Mammography use varies by age, with older women showing decreased use. The purpose of this research was to identify variables that affect screening use within two different age groups of women, those younger than 50 and those 50 and older. Predictor variables were identified using the Health Belief Model and Theory of Reasoned Action and included susceptibility, seriousness, benefits, barriers, health motivation, control, social influence, and experiential/demographic variables. A probability sample of 581 women aged 35 and older was included for analyses. Two measures of mammography compliance were tested: compliance with American Cancer Society (ACS) guidelines for the 5 years before the study and compliance with the ACS guidelines for the year before the study. An in-home interview was conducted by graduate research assistants. Compliance rates were significantly lower for women 50 and older than they were for younger women for both the 5-year compliance and the single year of compliance. Barriers were more significant for older women. Having a mammography suggested by a health care professional was most important in the older group, indicating that less weight may be given to personal decision making by this population. Higher socioeconomic status was significant with older but not younger women. For older women, interventions need to be directed toward both the physician and the individual woman. Programs that provide knowledge and address cost issues may be the most important primary components for younger women.