Recent recommendations from the U.S. Preventative Services Task Force suggest that screening mammography for women should be biennial starting at age 50 years and continue to age 74 years. With these recommendations in mind, we proposed a study to evaluate women at our institution in whom breast cancer is diagnosed within 1 year of a previously benign mammogram. A retrospective chart review was performed over a 4-year period. Only patients who had both diagnostic mammograms and previous mammograms performed at our institution and a pathologic diagnosis of breast cancer were included. Benign mammograms were defined as either Breast Imaging Reporting And Data System 1 or 2. Analysis of the time elapse between benign mammogram and subsequent mammogram indicative of the diagnosis of breast cancer was performed. A total of 205 patients were included. The average age was 64 years. From our results, 48 patients, 23 per cent of the total, had a documented benign mammogram at 12 months or less before a breast cancer diagnosis. One hundred forty-three (70%) patients had a benign mammogram at 18 months or less prior. This study raises concern that 2 years between screening mammograms may delay diagnosis and possible treatment options for many women.