Various causes of abnormal gastrointestinal motility may account for the symptoms of chronic intestinal pseudo-obstruction syndrome (CIIPS). Fasting gastrointestinal motility in humans is characterized by regular cyclic activity of the migrating motor complex (MMC), which may be used as an objective indicator of intestinal motility. The present study investigated MMC in five children with CIIPS (2 neurogenic and 3 nonneurogenic cases) using a perfused catheter system. The findings were compared with those for children with idiopathic constipation and Hirschsprung's disease. The gastrointestinal MMC was found to be abnormal with CIIPS, whereas it remained normal with idiopathic constipation and Hirschsprung's disease. The four CIIPS patients without any gastrointestinal MMC activity required total pareteral nutrition. There was significant improvement of intestinal motility over time in a patient with immaturity of ganglia, and there was gradual deterioration in a patient with hypoganglionosis. In conclusion, gastrointestinal motility studies provide objective diagnostic information in patients with intestinal dysmotility and can be used as an indicator of intestinal function during the treatment of CIIPS.