About 30% of patients with chronic upper motor neuron syndrome (UMNS) suffer from disabling spasticity-related pain not sufficiently correctable by conventional treatment. Delta9-tetrahydrocannabinol (Delta(9)-THC) was reported to add benefit in the treatment of pain in patients with multiple sclerosis (MS). The question arose whether synthetic cannabinoids with lower potential for psychotropic side effects could be effective as well. To evaluate the safety and efficacy of low dose treatment with the synthetic cannabinoid Nabilone (1 mg per day) on spasticity-related pain a placebo-controlled double-blind crossover trial was performed.11 out of 13 included patients completed the study. The 11-Point-Box-Test showed a significant decrease of pain under Nabilone (p < 0.05), while spasticity, motor function and activities of daily living did not change. 5 patients reported side effects: one moderate transient weakness of the lower limbs (Nabilone phase, drop out), three mild drowsiness (two Nabilone, one placebo) and one mild dysphagia (placebo). One patient was excluded from the study due to an acute relapse of multiple sclerosis (Nabilone phase, drop out). Nabilone 1 mg per day proved to be a safe and easily applicable option in the care of patients with chronic UMNS and spasticity-related pain otherwise not controllable.