Overnight sleep polygrams were recorded form 9 patients with Gilles de la Tourette syndrome (GTS). Six of 9 patients had abnormal electroencephalograms, but no specific abnormalities were detected. Body movements and twitch movements during sleep were analyzed. At all stages of sleep, body movements during sleep were more frequent in cases of GTS than those in normal controls. Twitch movements in stage REM of sleep were significantly increased in GTS. These results are consistent with the idea that GTS is due to an imbalance between the central neurotransmitters, catecholamine and serotonin.