OBJECTIVE: To examine the psychometric properties of the Danish version of the Medication Adherence Report Scale (DMARS-4) adapted to measure adherence to analgesic regimen among cancer patients. METHODS: The validated English version of the Medication Adherence Report Scale was translated into Danish following the repeated back-translation procedure. Cancer patients for the study were recruited from specialized pain management facilities. Thirty-three patients responded to the DMARS-4, the Danish Barriers Questionnaire II, The Danish version of Patient Perceived Involvement in Care Scale measuring the quality of patient-physician pain communication, and the Danish Brief Pain Inventory pain severity scale. RESULTS: A factor analysis of the DMARS-4 resulted in one factor. Mean (SD) score on the cumulative scale ranging from 4 to 20, with higher scores indicating better medication adherence, was 17.8 (0.42). The DMARS-4 scores were related to the measures of patients' concerns about pain management and patients' pain communication. The internal consistency of the DMARS-4 was 0.70. CONCLUSIONS: The DMARS-4 seems to be a valid and reliable measure of self-reported adherence to analgesic regimen in the context of cancer pain.