Patients affected by Parkinson's disease (PD) often complain of disturbed sleep resulting from nighttime motor disabilities such as nocturnal akinesia, tremor and rigidity, motor behaviour during REM sleep or periodic leg movements (PLM) during sleep. Sleep may also be affected by dopaminergic and anticholinergic drugs or coexisting depressive syndrome. Deep brain stimulation (DBS) of subthalamic nucleus (STN) effectively reduces PD motor disability. The aim of this study is to evaluate the sleep architecture modifications after STN DBS. We assessed five patients (two men and three women, mean age 63.8+/-3.3 years, with a mean history of PD of 13.8+/-4.9 years) who underwent STN DBS. The mean levodopa equivalent dosage (LED) was 1010+/-318 mg before surgery and 116+/-93 mg 3 months after surgery. Polysomnography (PSG) with audiovisual recordings was performed on two separate nights, the first assessment in the week before surgery and the second 3 months after surgery. Three months after surgery, PSG showed an increase in total sleep time, in the longest period of uninterrupted sleep, and in the percentage of stage 3-4 NREM sleep, while there was a reduction of wakefulness after sleep onset. PLM, apnea-hyopnea index and REM sleep behaviour disorder were unaffected by STN DBS. STN DBS seems to be an effective therapeutic option for the treatment of advanced Parkinson's disease because it improves the cardinal symptoms and also seems to improve sleep architecture.