This study investigated the effects of repeated split-belt treadmill (SBT) walking on gait ability in individuals poststroke. Twelve individuals with a first unilateral cerebral stroke (10 males; mean age 53 (SD 8.74); mean time poststroke 25 months (SD 23.5); 9 left-sided stroke) and initial step length (SL) asymmetry (ratio = 1.10-2.05) volunteered for the study. They were trained by physiotherapists from an outpatient rehabilitation center six times over 2-3 weeks using a SBT protocol. After only six sessions of training, all participants reduced their SL asymmetry from an average ratio of 1.39 to 1.17 (p = 0.002) and increased walking speed (p = 0.043). Improvements in symmetry and speed were retained over 1 month (p ≤ 0.008). No effect was observed in participants' endurance, assessed with the 6-min walk test. These findings suggest that the present SBT protocol has potential to be an efficient intervention to improve not only SL symmetry but also gait speed, in individuals poststroke.