Despite the effectiveness of mammography as a method to detect breast cancer in women ages 50 and older, many women do not obtain screening mammograms. This study used the self-reported mammography history and demographic information obtained during the screening of 2453 post-menopausal women ages 50 to 79 at the San Diego Women's Health Initiative (WHI) center. We used this data to examine individual and social factors that predict mammography use. The WHI center comprised two clinics, one of which focused on Hispanic recruitment and thus provided the opportunity to examine the roles of ethnicity, income, education, marital status, age, and access to medical services on mammography use. Bivariate analysis indicated that the following factors were all strongly associated with women having had a mammogram in the previous two years: having health insurance, a regular medical provider, an annual household income greater than $20,000, and a high-school diploma, as well as being 65 years or older or white (P < 0.001). Multiple logistic regression analysis demonstrated that, when adjusting for all of these factors, having a medical provider (P < 0.001) was significant. Having insurance (P = 0.04) was suggestive, but did not meet the multiple-comparisons significance cutoff of P = 0.006. After adjusting for the above factors, it was found that ethnicity was not significant. The results suggest that improved access to a regular provider could increase the use of screening mammography in underserved populations.