The asymmetrical nature of hemiparetic gait is well known; however, the role of walking asymmetry for speed performance is unclear. The purpose of the present study was to determine whether the range of walking speeds in chronic hemiparetic patients is associated with their gait asymmetry and postural sway. Twenty ambulatory patients with chronic unilateral supratentorial infarction were studied. Foot-ground contact patterns during swing and stance phases at various self-selected walking speeds were analyzed. The magnitude and direction of asymmetry in durations of stride phases were evaluated and compared with healthy subjects. Posturographic studies were performed to estimate the postural sway during quiet standing. Hemiparetic patients walked slower, more asymmetrically, and swayed more laterally favoring their nonaffected leg than did healthy persons. Although there was variability in durations of stride phases when comparing the two sides, a prolonged swing on the affected side and a prolonged stance on the nonaffected side were observed in all patients. The magnitude of asymmetry in stride phases varied among the patients; however, it was significantly higher than in controls (p < 0.03). Increased mean lateral sway during quiet standing was indicative of restricted velocity performance during walking. Patients with higher swing asymmetry achieved their maximum speed performance at lower velocity levels. However, the ability of patients to ambulate with a number of self-selected speeds was not associated with the magnitude of their overall gait asymmetry. Patients with right hemisphere lesions appeared to have less ambulatory ability than patients with left hemisphere lesions.