Prior studies have shown that older adults are susceptible to adverse medical events both during hospitalization and in the outpatient setting, but few studies have looked at the effects across the health care continuum. Reviewing multiple Medicare databases over a 7-year period, this study found that nearly 1 in 5 older adults experienced at least one adverse event, 62% of which originated in the ambulatory setting. Patients who experienced an adverse medical event had much higher mortality rates, though it should be noted that at baseline these patients were already older and sicker than the other cohort. Medicare expenditures increased sharply during an adverse medical event episode and remained high following the event. This study provides evidence that adverse events have a profound impact that lasts long after the initial incident.