In the present pilot study, we examined whether handgrip exercise by the non-affected hand of a stroke patient promotes venous return in the contralateral, affected arm. We calculated venous flow volume according to the venous diameter and the time-averaged mean flow velocity in the axillary vein measured by US. We found that rhythmic resistance exercise by the non-affected hand significantly increased venous flow velocity and volume in the affected upper limb, although the diameter of the axillary vein showed no statistically significant increase. Additionally, a moderate effect was observed for a difference in both venous flow velocity and volume between the measurements at baseline and during resistance exercise. These new findings suggest that exercise by the non-affected hand promotes venous return in the contralateral, affected upper limb in hemiplegic patients.