32 patients with fibromyalgia were randomized to receive either 0.5 mg nabilone or 10 mg amitriptyline over 2 weeks, with a possibility of doubling the dose after 1 week. Patients then underwent a 2-week washout period, and then received the opposite treatment to the first phase. The purpose of this study was to compare whether nabilone improved sleep compared to amitriptyline, and whether the two treatments were well-tolerated and had similar effects on mood, pain, and quality of life. Nabilone improved Insomnia Severity Index and LSEQ restful sleep subscale scores more than amitriptyline, and both treatments had similar effects on mood, pain, and quality of life. Both treatments were well-tolerated.