40 patients with fibromyalgia and chronic pain were randomized to receive increasing doses of nabilone or placebo. The purpose of the study was to determine whether nabilone significantly improved pain, fibromyalgia impact questionnaire (FIQ) scores, number and pain threshold of tender points over 4 weeks. Results indicated that weaker doses were not significantly effective, but nabilone 1 mg BID significantly improved VAS, FIQ and FIQ anxiety scale scores compared to baseline and placebo. Nabilone was associated with significantly more adverse effects. A total of 5 patients from the nabilone group and 2 placebo patients withdrew from the study.