Purpose: To investigate the effect of treadmill training applied simultaneously with gait related action observation on walking ability in chronic stroke patients. Methods: Sixteen chronic stroke patients participated in this study. Participants were randomly allocated into either the treadmill applied simultaneously with action observation training group (TAG) or treadmill applied simultaneously with landscape observation training group (TLG). The participants in both group underwent treadmill training for four weeks (a total of twelve minute, once a day, three times weekly for a four week period). All participants were measured to gait speed (10 m walking test, 10 MWT), gait endurance (6 minute walk distance, 6 MWD), dynamic gait index (DGI). In order to assure the statistical significance of the results, we used for SPSS 15.0 for windows. The Wilcoxon signed ranks test was used to compare pre-test and post-test result, and the Mann-Whitney U-test was employed for comparison between groups. Results: The 10 MWT, 6 MWD, DGI was significantly different between the TAG and the TLG group. Conclusion: According the results of this study, treadmill applied simultaneously with action observation (TAG) is effective intervention for improvement of walking ability in chronic stroke patient.