The goals of this study were to (1) provide preliminary reliability and validity of the Barriers to Treatment Adherence Questionnaire, developed for patients with fibromyalgia, and (2) examine barriers to adherence and general adherence to multimodal treatment during a 3-mo. period. A secondary goal was to explore in a focus discussion group format patients' perceptions of the adherence process and ways of managing the treatment program. 39 fibromyalgia patients were followed while participating in a combined outpatient program of physiotherapy, occupational therapy, nursing, and cognitive behavioral therapy. The Barriers to Treatment Adherence Questionnaire demonstrated good reliability. Construct validity of the Barriers to Treatment Adherence Questionnaire was supported through significant positive correlations with the General Adherence Scale at Months 1 and 3. In addition, a significant change was observed in scores on the Barriers to Treatment Adherence Questionnaire for the physiotherapy component of treatment, with scores decreasing between Months 2 and 3. Addressing barriers to improve adherence may maximize the benefit of treatment programs.