Little is known about validity of self-reported mammography surveillance among breast cancer survivors. Most studies have focused on accuracy among healthy, average-risk populations and none have assessed validity by electronic medical record (EMR) extraction method. To assess validity of survivor-reported mammography post-active treatment care, we surveyed all survivors diagnosed 2004-2009 in an academic hospital cancer registry (n = 1441). We used electronic query and manual review to extract EMR data. Concordance, sensitivity, specificity, positive predictive value, and report-to-records ratio were calculated by comparing survivors' self-reports to data from each extraction method. We also assessed average difference in months between mammography dates by source and correlates of concordance. Agreement between the two EMR extraction methods was high (concordance 0.90; kappa 0.70), with electronic query identifying more mammograms. Sensitivity was excellent (0.99) regardless of extraction method; concordance and positive predictive value were good; however, specificity was poor (manual review 0.20, electronic query 0.31). Report-to-records ratios were both over 1 suggesting over-reporting. We observed slight forward telescoping for survivors reporting mammograms 7-12 months prior to survey date. Higher educational attainment and less time since mammogram receipt were associated with greater concordance. Accuracy of survivors' self-reported mammograms was generally high with slight forward telescoping among those recalling their mammograms between 7 and 12 months prior to the survey date. Results are encouraging for clinicians and practitioners relying on survivor reports for surveillance care delivery and as a screening tool for inclusion in interventions promoting adherence to surveillance guidelines.