Objective:to investigate a high-intensity functional exercise (HIFE) group in hospitalised older adults. Design:assessor-blinded, randomised-controlled trial. Setting:sub-acute wards at a metropolitan rehabilitation hospital. Participants:older adults ≥65 years (n = 468) able to stand with minimum assistance or less from a chair and follow instructions. Intervention:'group' participants were offered a standing HIFE group three times a week and individual physiotherapy sessions twice a week. Control participants were offered daily individual physiotherapy sessions. Main outcome measures:the primary outcome measure was the Elderly Mobility Scale (EMS). Secondary measures included the Berg Balance Scale, gait speed, Timed Up and Go Test, falls, length of stay and discharge destination. Results:participants' mean age was 84.3 (7.1) years and 61% were female. There was no difference between groups for the improvement in EMS from admission to discharge (effect size -0.07, 95% confidence interval: -0.26 to 0.11, P = 0.446) and no difference in discharge destination, P = 0.904. Therapists saved 31-205 min/week treating group participants compared with control participants. Conclusion:the results suggest that a HIFE group programme combined with individual physiotherapy may improve mobility to a similar extent to individual physiotherapy alone in hospitalised older adults. Providing physiotherapy in a group setting resulted in increased therapist efficiency. A high-intensity exercise group with individual physiotherapy may be an effective and efficient method to provide care to older inpatients.