An extended family with chronic intestinal pseudo-obstruction which affected 11 of 54 members was studied. Patients presented with recurrent intestinal obstruction in childhood or adolescence: eight of the 11 died before the age of 30. Pedigree analysis showed four consanguineous marriages. The patients were all in the fifth generation and had established an autosomal recessive mode of inheritance. Histological, immunocytochemical, and electron microscopic studies were performed on a colectomy specimen from a surviving affected family member. Familial visceral myopathy was diagnosed--characterised by degeneration and collagenous replacement of both layers of the muscularis propria and the muscularis mucosae.