AimHow possible sarcopenia affects functional prognosis in patients with premorbid disability remains unclear. This study aimed to compare and investigate the impact of possible sarcopenia at admission on functional outcomes at discharge in patients with acute stroke with and without premorbid disability.MethodsThis cohort study enrolled patients who were consecutively admitted to a single center for acute stroke. Calf circumference and grip strength were measured within 7 days of admission, and possible sarcopenia was determined using the Asian Working Group for Sarcopenia 2019 criteria. The Functional Independence Measure (FIM) score at discharge during the acute phase was the primary outcome. To examine the impact of possible sarcopenia on FIM scores at discharge, patients were divided into two groups according to being with or without premorbid disability according to the modified Rankin Scale, and multiple linear regression analysis was performed in each group.ResultsThis study included 456 patients with acute stroke (median age, 80 years). In the premorbid‐disability group (n = 166), possible sarcopenia was present in 140 patients (84%). Patients without possible sarcopenia had significantly higher FIM scores at discharge compared with those with possible sarcopenia (P < 0.001). However, multiple linear regression analysis showed that possible sarcopenia was not associated with FIM scores at discharge in the premorbid‐disability group (β = −0.054, P = 0.346).ConclusionsThe results of this study demonstrated that a high rate of possible sarcopenia was observed in patients with stroke with premorbid disability; however, this did not affect functional prognosis. Geriatr Gerontol Int 2024; ••: ••–••.