The disabilities of the arm, shoulder and hand (DASH) questionnaire is a self-administered region-specific outcome instrument developed to measure upper-extremity disability and symptoms. The DASH consists mainly of a 30-item disability/symptom scale. We performed cross-cultural adaptation of the DASH to Swedish, using a process that included double forward and backward translations, expert and lay review, as well as field-testing to achieve linguistic and conceptual equivalence. The Swedish version's reliability and validity were then evaluated in 176 patients with upper-extremity conditions. The patients completed the DASH and SF-12 generic health questionnaire before elective surgery or physical therapy. Internal consistency of the DASH was high (Cronbach alpha 0.96). Test-retest reliability, evaluated in a subgroup of 67 patients who completed the DASH on two occasions, with a median interval of 7 days, was excellent (intraclass correlation coefficient 0.92). Construct validity was shown by a positive correlation of DASH scores with the SF-12 scores (worse upper-extremity disability correlating with worse general health), stronger correlation with the SF-12 physical than with the mental health component, correlation of worse DASH scores with worse self-rated global health, and ability to discriminate among conditions known to differ in severity. The Swedish version of the DASH is a reliable and valid instrument that can provide a standardized measure of patient-centered outcomes in upper-extremity musculoskeletal conditions.