Wilson's disease (WD) has neuro-anatomical, pathophysiological and neurochemical basis for sleep disturbances. The aim of the study was objective evaluation of the frequency and nature of sleep abnormalities using polysomnography (PSG) in patients with WD. The study included 25 subjects with WD (males, 18; age , 24.4 ± 9.25 years) and 25 healthy controls (all males; age, 33.1 ± 9.7 years). After phenotypic assessment and magnetic resonance imaging (MRI), sleep-related questionnaires were administered, and PSG was performed. Patients had significantly reduced total sleep-time (P=.001), sleep-efficiency (P=.001), percentage of deep sleep (P=.01), and REM-sleep (P=.04) with prolonged sleep-onset latency (P=.05) and latency to stage 2 (P=.02). Subgroup analyses of patients based on demographic and clinical parameters were done. Men had significantly more bradycardia both during awake (P=.002) and sleep (P=.03) states. Younger patients (<20 years) had frequent tachycardia (P=.01), higher Periodic Limb Movement (PLM) Index (P=.01) and lesser REM% sleep (P=.05). Patients on de-coppering therapy had prolonged REM-sleep-onset latency (P=.03) and mixed apnea events (P=.04). The isolated limb movements were more in the severe form of disease (P=.05) and in patients taking anticonvulsants (P=.03). This study, the first of its kind in literature, revealed significant sleep disturbances in patients with Wilson's disease.