Objective: Early mobility in mechanically ventilated patients is safe, feasible, and may improve functional outcomes. We sought to determine the prevalence and character of mobility for ICU patients with acute respiratory failure in U.S. ICUs. Design: Two-day cross-sectional point prevalence study. Setting: Forty-two ICUs across 17 Acute Respiratory Distress Syndrome Network hospitals. Patients: Adult patients (≥ 18 yr old) with acute respiratory failure requiring mechanical ventilation. Interventions: We defined therapist-provided mobility as the proportion of patient-days with any physical or occupational therapy-provided mobility event. Hierarchical regression models were used to identify predictors of out-of-bed mobility. Measurements and Main Results: Hospitals contributed 770 patient-days of data. Patients received mechanical ventilation on 73% of the patient-days mostly (n = 432; 56%) ventilated via an endotracheal tube. The prevalence of physical therapy/occupational therapy-provided mobility was 32% (247/770), with a significantly higher proportion of nonmechanically ventilated patients receiving physical therapy/occupational therapy (48% vs 26%; p ≤ 0.001). Patients on mechanical ventilation achieved out-of-bed mobility on 16% (n = 90) of the total patient-days. Physical therapy/occupational therapy involvement in mobility events was strongly associated with progression to out-of-bed mobility (odds ratio, 29.1; CI, 15.1-56.3; p ≤ 0.001). Presence of an endotracheal tube and delirium were negatively associated with out-of-bed mobility. Conclusions: In a cohort of hospitals caring for acute respiratory failure patients, physical therapy/occupational therapy-provided mobility was infrequent. Physical therapy/occupational therapy involvement in mobility was strongly predictive of achieving greater mobility levels in patients with respiratory failure. Mechanical ventilation via an endotracheal tube and delirium are important predictors of mobility progression.