INTRODUCTION: Aerobic exercise training after stroke has positive effects on quality of life, motor recovery, and aerobic endurance. The aim of this study was to investigate the effectiveness of anti-gravity treadmill gait training and underwater walking therapy on cardiorespiratory fitness, gait and balance in stroke survivors. METHODS: The study included 39 patients with a history of stroke who were admitted to our center between July 2017 and January 2018. The patients were randomly assigned to anti-gravity treadmill training, underwater walking therapy, or a control group. The aerobic capacity of the participants was evaluated with the 6-min walk test and cycle ergometer testing before and after the treatment. Balance was examined using the Berg Balance Scale (BBS). RESULTS: There was a statistically significant increase from pre- to post-treatment with regard to maximum heart rate and length of walking distance during 6-min walk test parameters in patients who underwent anti-gravity treadmill training (p < 0.05). The cycle ergometer training results showed significant improvements compared to baseline after treatment in patients who underwent anti-gravity training in terms of maximum heart rate attained during exercise stress testing, time to complete the test, rates of metabolic equivalents of task scores and peak oxygen consumption (p < 0.05). Improvements were also observed in ventricular repolarization indices including corrected QT intervals (QTc), Tp-e interval and Tp-e/QT, Tp-e/QTc ratio in the anti-gravity group (p < 0.05). BBS results showed no statistically significant difference in all groups (p > 0.05). CONCLUSION: The data of this study showed that anti-gravity treadmill training has favorable effects on cardiorespiratory fitness in stroke survivors.