Objectives: To identify variations in screening mammography expenditures, primarily out-of-pocket and total expenditures, of women 40-64 years of age in the United States and factors associated with variations. Methods: Retrospective analysis of data collected from the 2007 and 2008 Medical Expenditure Panel Survey (MEPS). The sample included 2020 women 40-64 years of age who received one mammogram in 2007 or 2008. Ordinary least squares regression was used to describe relationships among out-of-pocket mammography expenditures, total mammography expenditures, and out-of-pocket mammography expenditures as a percentage of total mammography expenditures and such independent variables as insurance status and type, income, region of the United States, and type of facility where a mammogram was received. Results: The average out-of-pocket expenditure for a mammogram in 2007 or 2008 was $33, representing 14.1% of the total mammogram expenditure ($266). After controlling for demographic and health factors, women who were uninsured, were from the Midwest, and had a mammogram at an office-based facility had greater out-of-pocket mammography expenditures. Women who were uninsured, lived in the South, and received their mammogram at an office-based facility had out-of-pocket mammography expenditures that represented a greater proportion of the total mammography expenditures. Conclusions: Large variations in out-of-pocket expenditures were observed among women with and without insurance and between insurance types, geographic regions of the United States, and types of facilities where mammograms were received. A higher financial burden of mammography screening among some subgroups of women may act as a barrier to future mammography screening.