INTRODUCTION. The Composite Autonomic Symptom Score (COMPASS 31) is a validated self-assessment questionnaire quantifying the severity and distribution of autonomic symptoms across six domains (orthostatic intolerance, vasomotor, secretomotor, gastrointestinal, bladder and pupillomotor functions) by scoring 31 clinically selected questions. The aim of this study was to translate into Danish and validate the Danish version of COMPASS 31. METHODS. The original (US) English version of the COMPASS 31 questionnaire was translated into Danish via forward/backward translation and validated in accordance with a protocol set forth by the Autonomic Group at the Mayo Clinic. Ten healthy controls and 20 patients with disorders associated with a variable degree of autonomic dysfunction were enrolled – all bilingual (Danish mother tongue, proficiency in English). RESULTS. A total of 20 patients (16 women, aged 48 + 17 years) and ten healthy controls (six women, aged 40 + 19 years) were included. Test-retest reliability was high with no consistent bias, and the Danish version of the COMPASS 31 significantly correlated with the English version of the COMPASS 31 in both total score and all sub-scores. Patients scored significantly higher on the COMPASS 31 questionnaire than healthy controls (34.0 (26.5-49.2) versus 2.3 (1.6-24.3) (median (interquartile ranges); p = 0.01). CONCLUSIONS. We present a Danish version of the COMPASS 31 – a validated self-reported questionnaire allowing for the quantification of autonomic dysfunction. We hope this Danish version will be implemented in both clinical practice and research settings in Denmark.