The prediction of mobility soon after a stroke should allow proper selection for rehabilitation and suggest the long-term prognosis of gait ability. Stable gait is related to midline body orientation and equilibrium mechanisms. We proposed that the sitting balance during the 1st, 2nd, or 3rd weeks after a hemiplegia could be a prognostic indicator for gait at 6 and 12 months. Sitting equilibrium measured in hospital was correlated with gait at the time of discharge and after 6 and 12 months, assessed by standing up, walking, and climbing stairs. The power in the affected limbs in hospital was also correlated with gait at those times. In the 134 patients followed up at 6 months, the correlation of equilibrium with gait at 6 months was r = 0.675 (p < 0.0001), and that of arm power with gait was r = 0.551 (p < 0.0001). Correlations with gait at 12 months were smaller and less meaningful. Assessment of sitting balance, even before the patient can stand, forms an important part of early management of the stroke patient.