This randomized trial evaluated the impact of physical and occupational therapy on function outcomes in mechanically vented patients in the ICU. Of 104 patients, 59% returned to independent functional status at discharge in the intervention arm compared with 35% in the control arm. Patients in the intervention arm also had shorter duration of delirium (P=0.02) and more ventilator-free days (P=0.05) compared to the control arm. Discontinuation due to patient instability occurred in 4% of all therapy sessions.