BACKGROUND: For individuals with lateral postural imbalance after stroke, the decision to adopt a cane for walking often is not based on objective findings. OBJECTIVE: The authors investigated the explanatory value of 2 posturographic criteria for lateral postural imbalance on the walking abilities of poststroke subjects. METHODS: Indices of postural asymmetry (percentage of body weight on the less loaded lower limb) and instability (mediolateral variance of center-of-pressure displacements) were measured in 40 healthy individuals and 52 patients (mean 94.2 days after first hemispheric stroke), who stood still on a double force platform. Cut-off values (mean ± 2 standard deviations) were calculated and compared. The predictive value of both postural indices on walking abilities with or without a cane was analyzed. RESULTS: Of the patients, 34.6% were unstable along the mediolateral axis (variance >7 mm(2)), and 44.2% were asymmetrical (body weight <40%); 30% needed a technical aid and 35% walked without a cane. The probability of being able to walk without a cane was less than 5% if the paretic lower limb was not loaded more than 40%. The postural instability index was less informative. CONCLUSIONS: This study suggests that patients who do not load more than 40% of their body weight on their paretic lower limb may benefit from the prescription of a cane.