Although diagnostic errors cause considerable morbidity and mortality, thus far organizations have focused on preventing errors that are more easily measured. This commentary provides two examples of organizational approaches to minimizing diagnostic error. In one, Maine Medical Center established a voluntary reporting system for diagnostic error coupled with a revised root cause analysis process to determine both cognitive and systems causes of these errors. In the other example, the Kaiser Permanente system leveraged their electronic medical record to establish electronic "safety nets" to identify patients at risk of diagnostic error. These mainly focused on ensuring appropriate follow-up of abnormal lab tests (particularly cancer screening tests) and sufficient monitoring of high-risk medications. As failure to appropriately follow-up on lab abnormalities is a common source of patient harm in ambulatory care, this system—which identified thousands of patients requiring urgent follow-up—likely averted many cases of preventable harm. An accompanying editorial by Dr. Hardeep Singh encourages health care organizations to develop processes for examining missed opportunities for making timely diagnoses.