The Barthel Index (BI) cannot be used to measure initial stroke severity or by extension, to stratify patients by severity in acute stroke trials because most patients are bedbound in the first few hours after stroke, either by their deficit or by medical directive. Our objectives were to clarify the threshold of acute BI for use in the prediction of subsequent independence in activities of daily living (ADL) and to assist in the definition of acute stroke rehabilitation goals. Subjects comprised 78 patients out of 191 inpatients admitted with acute stroke at our hospital during 2006-2007. The BI ADL score was divided into 2 ranges (BI> or =60 and < or =40), in a process similar to previous studies. During the acute period (from onset to approximately 3 weeks), all patients with a BI> or =40 could improve their ADL in 6 months. Patients with a BI< or =40 exhibited two ADL recovery outcomes (improved and no change) at 6 months. We also found that the skill level of basic activities related to standing was significant indicator of BI improvement (P<0.001). BI scores determined at approximately 3 weeks were reliable predictors of ADL disabilities at 6 months.