BACKGROUND:There is little research into interventions to increase activity levels of hospitalised older adults. AIMS:To assess the feasibility of using a physical activity monitor (PAL2) in hospitalized older adults and the effect of group exercise on activity levels. METHODS:Participants were hospitalized, ambulant adults ≥ 65 years randomized to individual physical therapy alone or combined with a high intensity exercise group and wore the PAL2 for five consecutive days. RESULTS:Only 33% of eligible participants agreed to participate with 19/30 (63%) complete data sets obtained; physical activity levels were low regardless of intervention. CONCLUSION:Acceptability of physical activity monitoring in hospitalized older adults was low and physical activity levels of those monitored was low across groups. To improve monitor compliance, future studies may consider excluding patients with specific comorbidities that impact on wear time, or selection of an alternative monitor.