The purpose of this study was to investigate the effects of attentional focus on static postural control in chronic stroke patients. Twenty four subjects diagnosed with chronic stroke participated in the experiment. All subjects maintained quiet standing on a force plate for 30 s with three attentional focus conditions: baseline (BL), internal focus (IF), andexternal focus (EF). No instructions regarding attentional focus were given to the subjects for the BL condition. The subjects were instructed to stand with their attention focused on their feet for the IF condition. Under the EF condition, the subjects were first instructed to check red markers indicated on the force plate. Then the subjects were asked to look front but to concentrate on the markers. The results demonstrated that the EF condition reduced the amount and instability of postural sway more than the other attentional focus conditions. The effects of attentional focus on postural sway were only exhibited in the mediolateral direction. This study suggests that directing attention focused on the movement effect that occurs in the external environment around the body may help stroke patients enhance the postural control of quiet standing.This might result from reduced asymmetric weight distribution with external focus. The present results provide a possible use of external focus to stabilize static posture in physical therapy for patients with stroke.