Objective: This study examined the age-associated rate of incomplete mammograms requiring additional testing based on Breast Imaging–Reporting and Data System (BIRADS) score. Methods: A retrospective, observational study design from a tertiary medical center was used to evaluate which explanatory variables significantly predicted whether a woman had an incomplete mammogram. An incomplete mammogram was defined as a BIRADS score of 0 (requiring further imaging), whereas a benign process was defined as a BIRADS score of 1 or 2. Explanatory variables included traditional clinical factors (age, race, and menopausal state). Results: During the study period, 20,269 subjects were evaluated. The majority of the patients were white (n = 12,955; 64.6%) and had a BIRADS score consistent with a benign finding (n = 17,571; 86.6%). Premenopausal state (odds ratio [OR], 1.38; 95% CI, 1.27–1.50), white race (OR, 1.18; 95% CI, 1.08–1.29), and younger age (OR, 1.38; 95% CI, 1.27–1.50) significantly increased the odds a woman had an incomplete study. Conclusions: In this cross-sectional, single-institution analysis, premenopausal state and white race are associated with an increased rate for incomplete mammograms. Patients should be counseled appropriately before the initiation of screening.