Smooth pursuit and optokinetic nystagmus were repeatedly examined in nine patients who sustained hemilateral brain injury. The follow-up period extended over several months of the in-hospital rehabilitation phase. Five of the patients were trained for 3-10 weeks to improve tracking responses using a biofeedback technique; the remaining four patients were not trained and served as a control group. In all patients in the first group gain responses improved and the recovery time constant increased at a rate higher than that in the untrained group. We suggest that our training procedure can be extended to other types of patients with impaired smooth pursuit tracking and may also benefit workers in need of good tracking performance.