Congenital megacystis with bilateral hydroureteronephrosis is most commonly associated with posterior urethral valves, prune-belly syndrome, vesicoureteral reflux, or nonrefluxing, nonobstructive megaureters. Among the other cause of congenital megacystis, megacystis-microcolon-intestinal hypoperistalsis syndrome(MMIHS), which is characterized by megacystis, microcolon and hypoperistalsis of the intestines with resultant abdominal distension, is a rare cause of functional obstruction of urinary tracts in childhood. It was first reported by Berdon, et al. in 1976, and only 89 cases have been reported until the present. There has been no report in Korea. We report a 2 month old female patient who exhibited intestinal malrotation, megacystitis, abdominal distension and hypoperistalsis. She did not show any evidence of microcolon, but her biopsy result exhibited degenerative changes of intestinal and cystic smooth muscle, pointing to a syndrome very similar to MMIHS.