Purpose: The purpose of this study was to examine the efficacy of modified constraint-induced movement therapy (mCIMT), which was applied to lower extremity, on strength and quality of life in patients with stroke. Methods: 30 patients with stroke were randomized to 2 groups. Both groups received first neurodevelopmental therapy (NDT) for 4 weeks as baseline treatment following which the study group received mCIMT and the control group received NDT for 2 weeks as experimental treatment. All were evaluated 3 times (pre-baseline treatment, post-baseline treatment, post-experimental treatment) through Motricity Index (MI), Stroke Impact Scale (SIS) and Stroke Specific Quality of Life (SS-QoL) scale. Results: The total score, mobility, self-care, upper extremity function, thinking, mood, family and social roles subdomain scores of the SS-QoL significantly increased in the study group, particularly during the experimental treatment period (p < 0.05). The amount of perceived recovery domain of SIS was greater in the study group during both the experimental and total treatment periods (p = 0.000). Significant improvement was observed in paretic lower extremity strength only in the study group for the total treatment period (p = 0.029). Correlations between the total change of scores in strength and quality of life and the changes in the experimental treatment period were found strong. Conclusion: This study shows that mCIMT is more effective than NDT in patients with stroke to improve paretic lower extremity strength and health related quality of life.