Three consecutive siblings with innumerable membranous gastrointestinal atresias, beginning at the prepyloric region and ending in the rectum, are reported. Microscopic examination of the small and large intestine showed multiple, tiny lumina each surrounded by a separate mucosa and muscularis mucosae but by a single muscular layer at the periphery. The pathological findings and hereditary character of these atresias suggest that a defect in recanalization during a solid stage of development involving the whole of the gastrointestinal tract may be the cause of these atresias.