Background. Mammography is widely known to reduce morbidity and mortality from breast cancer, but a population‐based assessment of mammography use and follow‐up of mammography findings has not been reported previously. Methods. An observational, population‐based, follow‐up study was conducted of all women having mammograms in the Greater Lansing, Michigan, metropolitan area, between June 1987 and June 1988. A total of 17,811 Greater Lansing women participated. The adherence of women to mammography screening guidelines was estimated, and mammography's utility to detect breast cancer was assessed through follow‐up review of breast biopsy results. Results. Thirty‐seven percent of the expected number of women 35 years of age and older had mammograms. Adherence to screening guidelines declined with age, and less than 5% (302 of 6700) of women 55 years of age and older reporting having annual mammograms. Seventy‐six percent of women reported that their physicians prompted the examination. The predictive value of a positive mammogram was 21.9% for women without symptoms and 32.4% for women with symptoms. Mammography's sensitivity and specificity for breast cancer detection were 71% and 98%, respectively. Conclusions. The study highlights the need to target mammography to women 50 years of age and older, underscores the importance of physicians in promoting mammography, and demonstrates the analytic value and limitation of mammography in clinical decision‐making.