Background and Purpose: Very early mobilization (VEM) is a distinctive characteristic of care in some stroke units; however, evidence of the effectiveness of this approach is limited. To date, only 2 phase II trials have compared VEM with standard care: A Very Early Rehabilitation Trial (AVERT) in Australia and the recently completed Very Early Rehabilitation or Intensive Telemetry after Stroke trial in the United Kingdom. The Very Early Rehabilitation or Intensive Telemetry after Stroke protocol was designed to complement that of AVERT in a number of key areas. The aim of this analysis was to investigate the impact of VEM on independence by pooling data from these 2 comparable trials. Methods: Individual data from the 2 trials were pooled. Overall, patients were between 27 and 97 years old, had first or recurring stroke, and were treated within 36 hours after stroke onset. The primary outcome was independence, defined as modified Rankin scale score of 0 to 2 at 3 months. The secondary outcomes included complications of immobility and activities of daily living. Logistic regression was used to assess the effect of VEM on outcome, adjusting for known confounders including age, baseline stroke severity, and premorbid modified Rankin scale score. FINDINGS-: All patients in AVERT and Very Early Rehabilitation or Intensive Telemetry after Stroke were included, resulting in 54 patients in the VEM group and 49 patients in the standard care group. The baseline characteristics of VEM patients were largely comparable with standard care patients. Time to first mobilization from symptom onset was significantly shorter among VEM patients (median, 21 hours; interquartile range, 15.8-27.8 hours) compared with standard care patients (median, 31 hours; interquartile range, 23.0-41.2 hours). VEM patients had significantly greater odds of independence compared with standard care patients (adjusted odds ratio, 3.11; 95% confidence interval, 1.03-9.33). Conclusions: Planned collaborations between stroke researchers to conduct trials with common protocols and outcome measures can help advance rehabilitation science. VEM was associated with improved independence at 3 months compared with standard care. However, both trials are limited by small sample sizes. Larger trials (such as AVERT phase III) are still needed in this field.