This study compared the responsiveness of the Hand 20 and the Japanese version of the disabilities of the arm, shoulder and hand (DASH-JSSH) questionnaires in carpal tunnel syndrome. The scores before and 3 months after surgery were used to calculate the standardized response mean and effect size. Of 57 patients enrolled in the study, 13 underwent open carpal tunnel release and 44 had endoscopic carpal tunnel release. The standardized response mean and the effect size of the Hand 20 scale were 0.60 and 0.54, respectively, and those of the disabilities of the arm, shoulder and hand scale were 0.39 and 0.36, respectively. Compared with the Disabilities of the Arm, Shoulder and Hand questionnaire, the Hand 20 questionnaire appears to have better responsiveness for assessing the effect of treatment by carpal tunnel release.