BACKGROUND: This study sought to determine the validity and responsiveness of the Disabilities of the Arm, Shoulder, and Hand (DASH) questionnaire in cubital tunnel syndrome. METHODS: Consecutive patients with cubital tunnel syndrome treated by anterior ulnar nerve transposition between September of 2009 and December of 2011 were reviewed retrospectively. Questionnaires were completed preoperatively and 1.5, 3, 6, and 12 months postoperatively. The relationship of the questionnaire to measures of pain, health status (Short Form-8), and pinch and grip strength was evaluated using Spearman's correlation coefficients. Responsiveness of the questionnaire was analyzed using Cohen's effect size, and was compared with responsiveness of the physical examination, pain, and Short Form-8 measures. RESULTS: The final cohort included 69 patients with isolated cubital tunnel syndrome and 39 with concurrent cubital and carpal tunnel syndrome. Questionnaire scores correlated as expected with other measures. Moderate to strong correlations were observed with pain visual analogue scale and Short Form-8 scores, and weak to moderate correlations were observed with pinch and grip strength. Effect sizes for the DASH questionnaire were small (<0.3) at 6 weeks and moderate (0.35 to 0.57) at 3, 6, and 12 months postoperatively in both groups. Pain visual analogue scale scores demonstrated large effect sizes (>0.8) at all postoperative time points, whereas Short Form-8 and pinch and grip strength were poorly responsive. CONCLUSION: The Disabilities of the Arm, Shoulder, and Hand questionnaire is a valid measure in cubital tunnel syndrome, and is moderately responsive to change beyond 3-month follow-up.