The prevalence of gastrointestinal amyloid was determined in 110 consecutive autopsy patients aged 85 years and older. Paraffin sections from the esophagus, stomach, small intestine, colon and rectum were stained with Congo red and inspected in polarized light. Amyloid was found in 38 patients (36%). Four patients had generalized amyloidosis and the remaining 34 revealed more localized varieties of amyloid. Immunohistochemical classification with a panel of antisera directed against five major amyloid fibril proteins displayed at least four different types of amyloid. Twenty cases exhibited amyloid of transthyretin origin, five cases were of lambda light chain origin and one case was of amyloid A-type. Thus far, unclassifiable amyloid deposits were found in 18 cases, 16 of which were strictly localized in subserosal veins. This consecutive autopsy series was compared with 98 randomly-selected bioptical gastrointestinal tissues with amyloid according to distribution pattern, sex, frequency of the various types of amyloid and associated diseases.