Introduction: Delirium is a common complication among older people who need care in the emergency department (ED). Mobility is an evidence-based non-pharmacologic strategy shown to reduce delirium and functional decline among older patients in the acute care setting. However, previous research has shown that compliance with mobility is important to achieve this decreased incidence of delirium. Gait tracking devices have been used in previous studies to accurately measure steps, engagement and intensity of physical activity in older hospitalized patients.The objectives of this study are to compare the feasibility and validate the accuracy of three accelerometer-based gait tracking devices. This is the first step in a program of research to objectively measure mobility among older ED patients as a potential marker of delirium risk. Methods: This is a prospective, observational study of patients 65 years of age and older during their ED visit. We excluded those with critical illness, unable to communicate or provide consent (language barrier, aphasia); and those with any ambulatory impediments. Consenting participants wear the gait trackers for the duration of their stay or for a minimum of 8 hour, and ambulate as normally as they would in their home. Devices were retrieved when the patient was admitted, discharged or, after 8 hours and the steps count was then recorded from an online interface. Our primary feasibility measure is the proportion of eligible patient for which we are be able to recover the tracker and record their steps. The primary validation endpoint will be the concordance between steps recorded by the gait tracking device compared to a gold standard manual step count over a fixed distance. We will report proportions with exact binomial 95% confidence intervals (CI) for feasibility and validity endpoints. Results: Preliminary data from an initial pilot phase includes 7 participants who wore a gait tracking device during their ED visit. Mean age was 79.7 years (+/−5.76) and 57% were females. Devices were worn by participants and recovered by research staff in all 7 cases (100%, 95% CI: 59 – 100). Data from online interface has been collected from 6 participants (85%, 95%CI: 42 – 99). Mean step count by observer was 86.17 +/− 4 (95% CI 82.2 – 90.2) and 70.3 +/− 4 (95%CI 66-74.3) by gait tracker. Conclusion: Our preliminary data suggests that use of gait-tracking devices in the ED is feasible.