Functional decline following hospitalization remains an important problem in health care, especially for frail older adults. Modifiable factors related to reduction in harms of hospitalization are not well described. One particularly pervasive factor is emergency department (ED) boarding time; time waiting from decision to admit, until transfer to an in-patient medical unit. We sought to investigate how the functional status of frail older adults correlated with the length of time spent boarded in the ED. We found that patients who waited for 24 hours or more exhibited functional decline in both the Barthel Index and Hierarchical Assessment of Balance and Mobility and an increase in the Clinical Frailty Scale from discharge to 6 months post discharge. In conclusion, there is a need for additional investigation into ED focused interventions to reduce ED boarding time for this population or to improve access to specialized geriatric services within the ED.