This prospective, observational study of physical rehabilitation in the ICU included 503 patients with acute lung injury from 11 ICU at 3 hospitals without an emphasis on early ICU rehabilitation. The study demonstrated that exposure to physical rehabilitation was low, with only 34% of patients ever receving PT in the ICU. Pateints, ICU, and hospital factors independently associated diagnose s, severity of illness, initiations of sedatines, coma and delirium status, and hospital site.