This study evaluates if the Disabilites of the Arm, Shoulder and Hand (DASH) questionnaire is an adequately responsive outcome measure in lateral extensor release for tennis elbow. To measure responsiveness (sensitivity to clinical change), 21 patients with operated tennis elbow completed the DASH questionnaire pre-operatively and again postoperatively. The effect size (2.03) and standardized response (1.54) mean that, as well as the correlation with patient satisfaction and the Roles & Maudsley score (10), the DASH questionnaire is a useful tool to evaluate the outcome of surgical treatment of tennis elbow.